Snake-Columbia Shrub-Steppe, Part II: Treasure Valley and Owyhee Plateau

The highest density of nesting raptors, thousand-foot-deep canyons, and a tall sand dune

States and Coordinates: Idaho-Nevada-Oregon, 41˚ to 45˚ North, 114˚ to 118˚ West

There are several distinct areas of the shrub-steppe ecoregion of the Columbia Plateau. For the purposes of this discussion, the ecoregion is subdivided into four sections, based on biological or geographic criteria. The first area, the Upper Snake River Plain, was discussed in Part I.

The second area is the Treasure Valley and Owyhee Plateau, the subject of this article. The Treasure Valley towns such as Boise, Nampa, Caldwell, Emmett, Ontario, and Weiser were settled around irrigated cropland, made possible by the numerous federal reservoirs and the water supply provided by the Snake, Boise, Payette, Owyhee, and Malheur Rivers. One unique community is the town of New Plymouth (1), N43˚58’ W116˚49’, which was established in 1895 along the Payette River. This was a planned community developed by the Plymouth Society of Chicago. Purchasers of shares were entitled to 20 acres and a town lot. The two town streets were developed in a horseshoe shape and separated by an 80-foot-wide park. The town plan is still evident today.

Surrounding the valleys are semiarid uplands and foothills which include such areas as the Morley Nelson Snake River Birds of Prey National Conservation Area (NCA)(2), areas around Mountain Home, and the Mount Bennett Hills and Picabo Hills. To the north of the Mount Bennett Hills is the unique Camas Prairie, an area of meadows and wetlands to the south of the Sawtooth Range in the vicinity of Fairfield and along US Route 20.

The area around Mountain Home was originally sagebrush steppe, but many sites are being invaded by cheatgrass. The sagebrush-perennial grassland ecosystem is being lost due to wildfire, heavy grazing, and perhaps other disturbances. In the Morley Nelson Snake River Birds of Prey NCA, shrublands in 1979 covered 51 percent of the area. Within 20 years, about half of the shrublands were lost, mostly due to fire.  Once cheatgrass is established, it feeds continuous fires that destroy more shrublands. Natural recovery of shrubland will be slow because of the arid conditions. This affects other wildlife as well. For example, blacktailed jackrabbits are associated with shrublands. Golden eagles prefer to eat jackrabbits, and the decline in prey will cause a reduction in the ability of the area to support golden eagles. Numbers of prairie falcons may also be affected. These birds eat ground squirrels. Up to five percent of the world’s population of Piute ground squirrels is found on the NCA, and the ground squirrels also are affected by broad-scale change to annual grassland (Sullivan 2005).

To the south and west of the Treasure Valley are the Owyhee Uplands, a high lava plateau which drains into the Snake River and covers most of southwestern Idaho and southeastern Oregon. Precipitous canyons of the Bruneau, Owyhee, Malheur, and Salmon Falls Creek cut through the uplands in places. The canyons are riddled with caves in many of the walls. Scattered volcanic buttes and cones rise out of the lava plains. The plateau is covered with semiarid vegetation such as sagebrush and grassland, but the Silver City Range rises above 6,500 feet in elevation and supports forests.

The volcanism that created the Owyhee Uplands created copious quantities of volcanic ash which blanketed the area periodically. Lava blocked creeks and created lakes and marshes. Volcanic ash then settled in the lakes, providing nutrients which promoted diatoms and algal blooms. These fell to the bottom and were deposited as siltstone and shale. Plant leaves, fruit, and flowers were deposited in these lakes and preserved as exquisite fossils due to the fine-grained sediments of the volcanic ash. The Succor Creek fossil flora, found in shale formed from volcanic ash in the Owyhee Uplands in Idaho and Oregon, is the largest Tertiary-period (15 million years ago) plant assemblage known from North America, with 160 species identified. Plants at that time were temperate with warm-temperate evergreens in lowlands. Shortly after this, the climate was in transition to a dryer, cooler one and eventually to the shrub-steppe seen today (Graham 2011).

There is one National Historic Landmark in theTreasure Valley-Owyhee Plateau. The Old US Assay Office, Idaho Historical Society, Boise, Idaho (N43˚37’ W116˚12’) was built in the 1870s to serve gold miners on the Clearwater, Wood, and Salmon Rivers and in the Boise Basin. By 1917, Idaho gold mines had yielded $400 million in gold. The office operated until 1933 and is today home of the State Historic Preservation Officer for Idaho.

There is one National Natural Landmark in theTreasure Valley-Owyhee Plateau. Crater Rings (3), part of the Morley Nelson Snake River Birds of Prey National Conservation Area, Idaho (N43˚9’ W115˚48’) are two adjacent pit craters, volcanic conduits which formed when rising lava came into contact with groundwater and exploded.

There are three National Forest areas in the Treasure Valley-Owyhee Plateau. The Boise National Forest, Idaho, includes the arid southern portion of the Idaho Batholith. The southern portion of this 2.6 million-acre forest, including the Danskin Mountains, extends into the Snake-Columbia shrub-steppe.   On the north slope of the Danskin Mountains overlooking the South Fork Boise River canyon is the Raspberry Gulch Research Natural Area (N43˚28’ W115˚40’).  This is a transition area at the forest-shrub steppe interface.  Elk Creek Exclosure Research Natural Area (N43˚37’ W115˚43’) is also a site in the shrub-steppe.  This area east of Arrowrock Reservoir is excluded from grazing animals for research purposes. The Ridge-to-Rivers Trail System is administered jointly with the City of Boise and the Bureau of Land Management (BLM), providing 130 miles of trails from Shafer Butte south to Lucky Peak Reservoir.  The forest also administers recreation areas along the Lucky Peak Reservoir and Anderson Ranch Reservoir within the ecoregion. Trinity Mountain Recreation Area is within the forest north of Mountain Home, Idaho, and provides lakes and wildflowers in mountain meadows. The Boise Ridge (4), extending from Lucky Peak (N43˚36’ W116˚4’) on the south to Hawley Mountain (N44˚0’ W116˚2’) on the north, is an IBA for migrating raptors.

A portion of the 2.5-million-acre Humboldt National Forest, Nevada, in the Santa Rosa Mountains and Jarbridge Mountains, extends into the Snake-Columbia shrub-steppe. See the Great Basin shrub-steppe ecoregion for a more complete description of this national forest area.

A portion of the 1.7-million-acre Sawtooth National Forest, Idaho, in the Soldier Mountains between Hill City and Ketchum, south of the South Fork Boise River, extends into the Snake-Columbia shrub-steppe ecoregion.

The National Landscape Conservation System in the Treasure Valley-Owyhee Plateau is represented by wilderness areas and wild and scenic rivers. Wilderness areas and units in the national wild and scenic river system are described separately below.  In addition, the Morley Nelson Snake River Birds of Prey NCA, Idaho (2), is a 485,000-acre area protecting America’s highest density of nesting raptors, including prairie falcon, kestrel, golden eagle, harriers, ospreys, and owls. There are 15 nesting species and an additional ten migratory species. The mostly rolling area is punctuated by the Snake River canyons and a series of flat-topped buttes. The Crater Rings NNL (see) is within the NCA, as is Swan Falls Reservoir (N43˚15’ W116˚23’), C.J. Strike Reservoir (N42˚58’ W115˚55’), Bruneau Dunes State Park (N42˚53’ W115˚42’) , and the Idaho National Guard Orchard Training Area (N43˚16’ W116˚11’), which has the Higby Cave archaeological site. Celebration County Park (N43˚18’ W116˚31’), at the west edge of the NCA on the Snake River, is a good viewing area.  Kuna Cave (N43˚25’ W116˚27’) is a lava tube south of Kuna.  The Oregon Trail south alternate route crosses the area near Henderson Flats and Wild Horse Butte (N43˚8’ W116˚20’) and in the area of C.J. Strike Reservoir.  The Idaho Centennial Trail crosses the southeastern portion of the NCA east of Bruneau Dunes State Park.  Some of the buttes include Kuna Butte (N43˚26’ W116˚27’), Coyote Butte (N43˚20’ W116˚-22’), Guffey Butte (N43˚17’ W16˚33’), Wild Horse Butte (N43˚8’ W116˚20’), Castle Butte (N43˚6’ W116˚17’), Jackass Buttes (N43˚5’ W116˚13’), Black Butte (N43˚5’ W116˚11’), Big Foot Butte (N43˚12’ W116˚13’), Cinder Cone Butte (N43˚13’ W116˚0’).  The Chalk Flat area (N42˚59’ W115˚33’) along I-84 is also within the NCA.

Recreation lakes in the Treasure Valley and Owyhee Plateau were built for irrigation, recreation, and hydropower purposes.  On the Snake River are three Idaho Power Reservoirs. Bliss Dam(5), Idaho Power, Idaho (N42˚55’ W115˚4’), is located on the Snake River six miles west of Bliss. C.J. Strike Dam and Reservoir, Idaho Power, Idaho (N42˚57’ W115˚57’) is located on the Snake River ten miles west of Bruneau on State Route 78. Idaho Power manages its reservoir lands with the state as a wildlife management area. On the north side of the Bruneau Creek embayment is a remnant Oregon Trail segment. Swan Falls Dam, Idaho Power, Idaho (N43˚15’ W116˚23’) is located on Swan Falls Road 17 miles south of Kuna. It is the oldest hydroelectric dam in Idaho, dating to 1901. Both C.J. Strike and Swan Falls Reservoirs are within the NCA. The backwaters of Brownlee Reservoir in the Blue Mountains ecoregion also extend into the Snake River shrub-steppe near Huntington, Oregon.

In the Salmon Falls Creek canyon south of Twin Falls is Salmon Falls Creek Reservoir(6), BLM, Idaho (N42˚12’ W114˚44’).  Lud Trexler Park is a reservoir recreation area on this irrigation reservoir near Jackpot, Nevada.

There are three reservoirs in the Mount Bennett Hills-Camas Prairie area, which are in the Big Wood River watershed. Mormon Reservoir (7), Twin Lakes Reservoir and Irrigation Company, Ltd., Idaho (N43˚15’ W114˚49’) is in the Camas Prairie and is an IBA for nesting shorebirds and gulls. Magic Reservoir (8), Magic Reservoir Hydroelectric, Inc., Idaho, (N43˚15’ W114˚21’) is on the Big Wood River on US 20 east of Fairfield. It is an IBA for gulls, terns, long-billed curlew, trumpeter and tundra swans.  Thorn Creek Reservoir, BLM, Idaho ( N43˚12’ W114˚36’) is a reservoir recreation site is in the Mount Bennett Hills north of Gooding off of Route 46.

On the Boise River are four federal reservoirs. Anderson Ranch Reservoir (9), Bureau of Reclamation, Idaho (N43˚23’ W115˚25’) is on the South Fork of the Boise River. It provides irrigation for the Arrowrock Division of the Boise Project. The Boise and Sawtooth National Forests manage Anderson Ranch Reservoir recreation areas. Arrowrock Reservoir (10), Bureau of Reclamation, Idaho (N43˚36’ W115˚55’), is located on the Boise River in the Boise National Forest. It stores irrigation water for the Boise project. Lucky Peak Reservoir(11), US Army Corps of Engineers, Idaho (N43˚32’ W116˚2’) is operated in conjunction with the Bureau of Reclamation’s Boise project irrigation lakes. The Boise River IBA and Boise Greenbelt extends downstream from the reservoir to Garden City.

The Boise River Diversion Dam (11), Bureau of Reclamation, Idaho (N43˚32’ W116˚6’), is seven miles upstream from Boise. This dam diverts water to Lake Lowell and the New York Canal for irrigation. The Boise River IBA extends from Lucky Peak Dam to Garden City including this area and is an IBA for bald eagles, waterfowl, and colonial nesting birds.

Two dams store water from the Boise River for irrigation use. Hubbard Dam (12), Bureau of Reclamation, Idaho (N43˚31’ W116˚21’), is 12 miles southwest of Boise and stores water from the New York Canal. Lake Lowell (13),Bureau of Reclamation, Idaho (N43˚35’ W116˚43’), also stores irrigation water from the Boise River and is an artificial reservoir in a low spot surrounded by three dikes.  Surrounding lands are managed as Deer Flat National Wildlife Refuge (NWR), described below.

Blacks Creek Reservoir (12), BLM, Idaho (N43˚28’ W116˚9’), is also in the Boise River watershed and is located at I-84 exit 64.  This small reservoir has mudflats used by waterfowl and shorebirds and is an IBA.

On the Owyhee River is Owyhee Reservoir (14), Bureau of Reclamation, Oregon (N43˚38’ W117˚15’). This irrigation storage lake diverts water to two irrigation canals along the Snake River, providing water for 105,000 acres. Construction of Owyhee Dam was a proving ground for later construction of Hoover Dam in Arizona-Nevada. Water is diverted into a tunnel and exits three miles north of the dam. From this point, the North Canal extends 61.5 miles north to the Snake River, crossing the Owyhee and Malheur Rivers before joining the Snake River downstream from Weiser, Idaho. A second tunnel conveys water to the South Canal, which in turn conveys water east to the Snake River near Homedale, Idaho. Lake Owyhee State Park provides recreation on the 35-mile-long reservoir. Leslie Gulch (N43˚19’ W117˚18’) and Runaway Gulch on the south end of the reservoir make up a BLM recreation area noted for volcanic ash tuff formations.

Antelope Reservoir (15), Jordan Valley Irrigation District, Oregon (N42˚54’ W117˚14’), is on US 95 south of Jordan Valley. This irrigation storage and hydroelectric reservoir is on Jack Creek, a tributary to the Owyhee River in Oregon; reservoir recreation is managed by the BLM.

On the Malheur River and tributaries are four federal reservoirs in the Snake-Columbia shrub-steppe.  Beulah Reservoir and Agency Valley Dam (16), Bureau of Reclamation, Oregon (N43˚56’ W118˚9’), on the North Fork of the Malheur River, is an irrigation storage reservoir and part of the Vale Project. It is fed by hot springs in the upper end of the lake. Recreation is managed by Malheur County. Warm Springs Reservoir (17), Bureau of Reclamation, Oregon (N43˚36’ W118˚14’) is on the Middle Fork of the Malheur River 13 miles southwest of Juntura; this facility stores water from the Malheur River for release to the Harper Diversion Dam and Vale Canal. The reservoir attracts migratory waterfowl. Harper Diversion Dam (18), Bureau of Reclamation, Oregon (N43˚47’ W117˚45’) is on the Malheur River 20 miles upstream from Vale. Water is diverted into the Vale Canal, which extends 74 miles to Jamieson.  Bully Creek Reservoir, Dam, and Diversion Dam (19), Bureau of Reclamation, Oregon (N44˚1’ W117˚24’) is nine miles northwest of Vale and is an irrigation storage reservoir in the Vale Project. The reservoir attracts migratory waterfowl. Recreation is managed by Malheur County.

On the Payette River in the Snake-Columbia shrub-steppe is the Black Canyon Diversion Dam (20), Bureau of Reclamation, Idaho  (N43˚55’ W116˚25’). Located on the Payette River at Emmett, this project diverts irrigation water as part of the Payette Division of the Boise Project

The National Trail System in theTreasure Valley-Owyhee Plateau is represented by the Oregon National Historic Trail and two national recreation trails (NRTs).  The following are Oregon National Historic Trail sites.

Main Route

  • Three Island Crossing State Park (21), Idaho  (N42˚56’ W115˚20’), is at Exit 120 on I-84 at Glenns Ferry. This historic river ford contains wagon ruts. Crossing the Snake River was risky, and emigrants risked losing all their livestock and supplies if things were deeper than expected or a wagon wheel dropped into a hole. An alternate Oregon Trail (South Alternate Route) continued on the south side of the Snake River to avoid this risk. The three islands are visible just downstream from the state park. An Oregon Trail History and Education Center is at the park.  The south side preserves a section of the trail as it descended to the river.

North Alternate Route

  • Teapot Dome Hot Springs, Idaho (N43˚9’ W115˚30’) were along the Oregon Trail as it followed the Hot Springs Creek.  The springs are now dry due to irrigation diversions.
  • Rattlesnake Station, Idaho (N43˚12’ W115˚33’) was located at the crossing of present-day US Route 20 on Rattlesnake Creek at the base of a mountain; this was later a stage station stop in the 1870s.
  • Canyon Creek Station, Idaho (N43˚16’ W115˚42’), was at a creek crossing providing lush green grass and water for Oregon Trail travelers; a stage station was built here in 1873.
  • Ditto Station, Idaho (N43˚21’ W115˚49’)
  • Indian Creek Station, Idaho (N43˚25’ W115˚54’)
  • At Bonneville Point (11), BLM, Idaho (N43˚30’ W116˚2’), travelers were rewarded with a panoramic view of the Treasure Valley. It is accessible from Exit 64 on I-84. A mountain bike trail connects with the Boise Greenbelt.
  • Oregon Trail Historic Reserve, BLM, Idaho (N43˚33’ W116˚8’), overlooks Boise and contains segments of the original Oregon Trail ruts and trails.
  • Ward Massacre Park (22), Canyon County, Idaho (N43˚41’ W116˚37’) was the site of an Indian attack on a 20-member Oregon Trail party in 1854; two children were survivors. The site is two miles south of Middleton and one mile north of US 20-26 on Lincoln Road off of Middleton Road.
  • Canyon Hill Ruts, Caldwell, Idaho (N43˚41’ W116˚41’)
  • Fort Boise (23), Fort Boise Wildlife Management Area, Idaho (N43˚49’ W117˚1’) was constructed in 1834 by Hudson’s Bay Company at the confluence of the Boise and Snake Rivers; the fort was abandoned in 1844 due to flooding. A current structure in Parma is a replica.

South Alternate Route

  • Bruneau Dunes State Park, Idaho (N42˚54’ W115˚42’) was a landmark along the South Alternate Route.
  • C.J. Strike Ruts, Idaho (N42˚57’ W115˚56’) are within the C.J.Strike Wildlife Management Area. Trail ruts are on the north side of the Bruneau Creek arm of the reservoir.
  • Utter Disaster Site, Idaho (N43˚7’ W116˚18’) was the site of the greatest loss of life on the Oregon Trail in 1860. A two-day encounter with Indians resulted in a loss of 11 emigrants and 30 Indians. The emigrant survivors escaped without their supplies and walked 75 miles downriver to the Owyhee River junction. While awaiting rescue, other emigrants died of starvation or other Indian attacks. The site is at Henderson Flats, four miles north of State Route 78 on Wees Road in the Morley Nelson Snake River Birds of Prey NCA.
  • Sinker Creek Segment, Idaho (N46˚9’ W116˚25’), is west of Henderson Flats and east of Murphy.  This intact trail segment crosses the NCA.
  • Givens Hot Springs (26), Idaho (N43˚25’ W116˚42’), is a commercially operated park on State Route 78. It was a minor landmark along the South Alternate Route. The spring area was homesteaded in 1881 and is still owned by the same family.

Main Route

  • Captain Keeney Pass (24), BLM, Oregon (N43˚55’ W117˚11’), is a 3,000-foot elevation pass south of Vale on the divide between the Owyhee River and Malheur River. Trail swales can still be seen.
  • Alkalai Springs Segment, Oregon (N44˚7’ W117˚14’) is between Vale and Farewell Bend State Recreation Area.  It is a remnant segment of the trail that can be visited.
  • Farewell Bend State Recreation Area (25), Oregon (N44˚18’ W117˚14’), is where the trail left the Snake River and began the crossing of the more well-watered Blue Mountains.

Two NRTs are in the Treasure Valley-Owyhee Plateau area. Hulls Gulch Interpretive Trail, BLM, Idaho (N43˚39’ W116˚9’), is six miles north of Boise on 8th Street Road; this three mile loop trail descends to a waterfall and riparian area in a sagebrush-steppe habitat. Weiser River NRT (26), Friends of the Weiser River Trail, Idaho, is an 85-mile rail trail owned and managed by a friends group.  It begins in the south at Weiser (N44˚15’ W116˚57’), continues to Rebecca (N44˚15’ W116˚51’) and Presley (N44˚16’ W116˚46’), and then continues north through desert canyons to forests in the Blue Mountains. The northern end is at Rubicon on US Route 95 four miles west of New Meadows in the Blue Mountains.

The National Wild and Scenic River System is extensively represented in the Owyhee Plateau. The Bruneau River, West Fork Bruneau River, Jarbridge River, and Sheep Creek are described under the Bruneau-Jarbridge Rivers Wilderness. Big Jacks Creek, Cottonwood Creek, Duncan Creek and Wickahoney Creek are described under the Big Jacks Creek Wilderness. Little Jacks Creek is described under the Little Jacks Creek Wilderness. Battle Creek, Deep Creek, Dickshooter Creek, Red Canyon, and South Fork Owyhee River are described under the Owyhee River Wilderness.

The Owyhee River, BLM, Idaho-Oregon, includes 67 miles in Idaho (see Owyhee River Wilderness) and 120 miles in two segments in Oregon. The Oregon segments are all in the Owyhee River canyon upstream from Owyhee Reservoir (N43˚18’ W117˚29’) and include Wrangler Basin, The Hole in the Ground, Lambert Rocks Lava Flow, and Crooked Creek (N42˚53’ W117˚42’) in the lower segment. The upper segment begins at China Gulch (N42˚49’ W117˚37’) and includes Soldier Creek, Skull Creek, Dreary Pasture, Three Forks, Big Antelope Canyon, West Little Owyhee River, and Beaver Charlie Breaks (N42˚22’ W117˚3’).  Soldier Creek Road is a 28-mile road that provides overlooks into the Owyhee River Canyon between Antelope Reservoir and Three Forks of the Owyhee.

The North Fork Owyhee River, BLM, Idaho-Oregon, includes 20.8 miles designated in Idaho and 9.6 miles designated in Oregon. For the Idaho section see North Fork Owyhee Wilderness. The Oregon section  begins at the Owyhee confluence (N42˚33’ W117˚10’) and includes Three Forks, Cherry Creek side canyon, and Squaw Creek side canyon (N42˚34’ W117˚3’).

The West Little Owyhee River (27), BLM, Oregon, river designation includes the entire river from headwaters east of Route 93 on the Fort McDermitt Indian Reservation at N42˚6’ W117˚34’ downstream to the confluence with the Owyhee at N42˚27’ W117˚13’, a distance of 57.6 miles. This is all in Louse Canyon. The Oregon Desert Trail follows the river.

There are six Wilderness Areas in the Owyhee Plateau of Idaho. The Bruneau-Jarbridge Rivers Wilderness (28), BLM, Idaho, is a 90,000-acre wilderness of river canyons with rock spires and volcanic cliffs. The boundaries mostly follow river canyons. Many of the river canyons are lined with caves and natural arches. Four river segments within the wilderness are also designated Wild Rivers. The Idaho Centennial Trail parallels the eastern side of the wilderness from Murphy Hot Springs to its north end.  The wilderness includes the following features:

  • Bruneau Canyon from mile 20.6 near Indian Bath Tub (N42˚45’ W115˚44’) upstream to Cedar Tree Trail Lakes, five miles past the Jarbridge River (N42˚16’ W115˚42’; at the Jarbridge some maps call it West Fork Bruneau upstream); 39 miles of the Bruneau and 0.4 miles of the West Fork at Indian Hot Springs N42˚20’ W115˚39’ are a Wild River
  • Miller Water Canyon (N42˚38’ W115˚42’, Bruneau River mile 31.5L) upstream for three miles
  • East Fork Canyon/Clover Fork (N42˚35’ W115˚36’, mile 37.5 R Bruneau River) from the Bruneau River upstream seven miles to Winter Camp
  • Sheep Creek from mile 46L on the Bruneau River upstream 25.6 miles to near James Place (N42˚17’ W115˚46’); all 25.6 miles are a Wild River; the canyon walls are noted for numerous caves and a natural arch
  • Blackstone Desert (N42˚29’ W115˚37’)
  • J-P Point overlooking the Bruneau River (N42˚27’ W115˚37’)
  • Louse Creek from Sheep Creek upstream three miles (N42˚24’ W115˚47’)
  • Bighorn Country (N42˚23’ W115˚45’) on Sheep Creek
  • Mary’s River upstream three miles from Sheep Creek (N42˚19’ W115˚48’)
  • Cave Draw on the Bruneau River (N42˚26’ W115˚38’)
  • Stiff Tree Draw on Bruneau River (N42˚24’ W115˚37’)
  • Jarbridge River from the confluence with the Bruneau  at mile 49R (N42˚20’ W115˚39’) upstream 28.8 miles to Murphy Hot Springs (N42˚3’ W115˚23’); all 28.8 miles are a Wild River; the canyon has numerous caves in the walls
  • Poison Creek (N42˚15’ W115˚31’) from Jarbridge River Mile 8.5R upstream two miles
  • Arch Canyon (N42˚13’ W115˚33’) from the Jarbridge River mile 10L upstream for seven miles
  • Arch Table (N42˚10’ W115˚31’) on the Jarbridge River
  • Dorsey Creek (N42˚7’ W115˚30’) from Jarbridge River mile 17.5L upstream for two miles
  • Columbet Table (N42˚3’ W115˚25’) on the Jarbridge River
  • Hot Springs Bench (N42˚19’ W115˚41’) on the Bruneau River
  • Cedar Tree Trail Lakes (N42˚16’ W115˚41’) on the Bruneau River

Big Jacks Creek Wilderness (29), BLM, Idaho, is a 53,000-acre sagebrush-covered 600-foot-deep canyon.  Wild River segments include Big Jacks Creek (35 miles, all within the wilderness; south end N42˚30’ W116˚12’; north end N42˚45’ W116˚0’), Cottonwood Creek (N42˚32’ W116˚5’, 2.6 miles from Big Jacks Creek upstream to the wilderness boundary), Duncan Creek (N42˚33’ W116˚1’, 0.9 miles upstream from confluence with Big Jacks Creek), and Wickahoney Creek (N42˚34’ W116˚0’, 1.5 miles upstream from confluence with Big Jacks Creek).  Other features are Willies Canyon and Point (N42˚33’ W116˚7’), Harvey Point (N42˚32’ W116˚5’), Dry Canyon (N42˚32’ W116˚6’), Hill Pasture (N42˚33’ W116˚3’), Zeno Canyon (N42˚30’ W116˚4’), and The Island (N42˚29’ W116˚3’).

Little Jacks Creek Wilderness (30), BLM, Idaho, is a 51,000-acre sagebrush-covered basalt dome with canyons 1,000 feet deep.  Features are Horse Basin (N42˚41’ W116˚6’), Rattlesnake Creek (N42˚39’ W116˚7’), The Hat (N42˚36’ W116˚12’), and Perjue Canyon -Between the Creeks (N42˚45’ W116˚14’).  Little Jacks Creek is a Wild River for 12.4 miles from O X Prong (N42˚39′ W116˚15’) downstream to the wilderness boundary (N42˚43’ W116˚7’).

Owyhee River Wilderness (31), BLM, Idaho, is a 267,300-acre wilderness which includes the Grand Canyon of the Owyhee and tributaries from the Oregon state line upriver to the Duck Valley Indian Reservation. The wilderness is part of the Owyhee Uplands IBA for green-tailed towhee, ferruginous hawk, and black-throated grey warbler. Plateau areas in addition to canyon areas are included; the plateaus feature fields of lupine and bighorn sheep.  Six of the canyons are designated Wild Rivers. Features include:

  • Owyhee River from the Oregon State line at N42˚19’ W117˚2’, 67.3 miles upstream to the Duck River Indian Reservation boundary at N42˚6’ W116˚24’; the entire 67.3 miles are a Wild River
  • Cavieta Hill at N42˚21’ W117˚1’
  • Dukes Creek (N42˚19’ W116˚59’) from the right bank Owyhee River upstream to its headwaters
  • Bald Mountain Canyon (N42˚19’ W116˚56’), from the confluence on the right bank Owyhee River upstream to its headwaters
  • South Fork Owyhee, a 500-foot deep canyon on the left bank of the Owyhee River at N42˚16’ W116˚53’ extending 31.4 miles upstream to Nevada State line at N42˚0’ W116˚43’; all 31.4 miles are a Wild River
  • Juniper Basin at N42˚15’ W116˚55’on South Fork Owyhee, left bank
  • Spring Creek Basin at N42˚11’ W116˚55’ on South Fork Owyhee, left bank
  • Little Owyhee River from confluence with South Fork Owyhee, left bank at N42˚10’ W116˚52’ upstream nine miles to Star Valley at N42˚2’ W116˚57’
  • Halogeton Flat at N42˚7’ W116˚53’ on Little Owyhee River, right bank
  • Grassy Ridge (N42˚10’ W116˚49’) on South Fork Owyhee, right bank
  • Bull Camp Butte (N42˚0’ W116˚41’) on South Fork Owyhee, right bank
  • Red Canyon (N42˚19’ W116˚51’) on Owyhee River, right bank; 4.6 miles are a Wild River
  • Petes Creek (N42˚20’ W116˚53’) from Red Canyon upstream to Bull Basin
  • The Tongue (N42˚17’ W116˚51’) on Red Canyon, left bank
  • Red Basin Creek (N42˚20’ W116˚49’) on Owyhee River right bank
  • Ryan Pasture (N42˚16’ W116˚48’) on Owyhee River left bank
  • Cherry Gulch and the Dome (N42˚15’ W116˚42’) on Owyhee River right bank
  • Porcupine Creek (N42˚18’ W116˚41’) on Owyhee River right bank
  • Deep Creek, a vertical-walled canyon beginning at the Owyhee River right bank (N42˚16’ W116˚39’) and extending upstream for 13.1 miles; all 13.1 miles are a Wild River
  • White Cow Basin (N42˚18’ W116˚39’) on Deep Creek right bank
  • Sheep Hills (N42˚19’ W116˚39’) on Deep Creek right bank
  • Dickshooter Creek/Black Canyon, from left bank Deep Creek confluence at N42˚20’ W116˚37’ upstream for 11 miles to N42˚23’ W116˚33’; 9.3 miles are a Wild River
  • Dickshooter Ridge (N42˚18’ W116˚34’) on right bank Owyhee River
  • Piute Creek (N42˚14’ W116˚38’) on left bank Owyhee River upstream for three miles
  • Battle Creek, a 200-foot deep canyon on the right bank Owyhee River with vertical walls one eighth mile apart which extends from the confluence at N42˚14’ W116˚32’ upstream for 23.4 miles to Lower Battle Creek Crossing at N42˚23’ W116˚22’; all 23.4 miles are a Wild River
  • Freshwater Draw (N42˚18’ W116˚29’) on Battle Creek right bank
  • Battle Creek Lakes (N42˚16’ W116˚25’) on Battle Creek left bank
  • Kelly Park (N42˚18’ W116˚28’) on Battle Creek right bank
  • The Tules (N42˚13’ W116˚30’) on Owyhee River left bank
  • Windy Point (N42˚11’ W116˚30’) on Owyhee River right bank
  • Juniper Creek/Hole Up Canyon (N42˚8’ W116˚27’) on Owyhee River left bank
  • Jarvis Pasture (N42˚10’ W116˚27’) on Owyhee River right bank
  • Juniper Basin (N42˚8’ W116˚26’) on Owyhee River left bank
  • Hold Up Canyon (N42˚9’ W116˚24’) on Owyhee River right bank

The 43,000-acre North Fork Owyhee Wilderness (32), BLM, Idaho, is characterized by river canyons more than 1,000 feet below sagebrush and grassland plateaus.  Located three miles east of the state line on the North Fork, the wilderness includes lower Juniper Creek (N42˚36’ W116˚57’), Cabin Creek (N42˚37’ W116˚55’), lower Pleasant Valley Creek and Pleasant Valley Table (N42˚35’ W116˚51’), Noon Creek (N42˚37’ W116˚52’), Current Creek (N42˚38’ W116˚46’), and upper Nip and Tuck Creek (N42˚39’ W116˚43’).

Pole Creek Wilderness (33), BLM, Idaho, is also characterized by river canyons more than 1,000 feet deep; the wilderness is 12,000 acres.  Features are Avery Table (N42˚34’ W116˚37’), Bullhead Basin (N42˚35’ W116˚37’), Camel Falls (N42˚33’ W116˚37’), Wagon Box Basin (N42˚31’ W116˚34’), Camas Creek (N42˚32’ W116˚33’), and Henley Basin (N42˚32’ W116˚35’).

There is one National Wildlife Refuge in the Treasure Valley.  Deer Flat NWR (13), Idaho-Oregon, includes two distinct habitats.  Part of the refuge in the Treasure Valley surrounds 9,000-acre Lake Lowell (N43˚34’ W116˚42’) and is a waterfowl-shorebird refuge. Another portion includes 101 river islands  that make up 800 acres along a 100-mile reach of the Snake River between the Snake River Birds of Prey NCA (Rail Island N43˚18’ W116˚31’) and Farewell Bend State Recreation Area (Whitehill Island, Idaho N44˚17’ W117˚12’. The islands are waterfowl nesting areas. Most of the islands are between Celebration County Park (N43˚18’ W116˚31’) and Riverside, Idaho (N43˚28’ W116˚46’). Other island concentrations are between Adrian (N43˚43’ W117˚5’) and the Owyhee River confluence (N43˚46’ W117˚2’), Apple Valley (N43˚50’ W117˚1’), Nyssa (N43˚52’ W116˚59’), Payette (N44˚7’ W116˚55’), Weiser (N44˚12’ W116˚58’ and N44˚15’ W117˚9’). The two most downstream islands, Whitehill N44˚17’ W117˚12’ and Fenzl N44˚16’ W117˚10’, are submerged by Brownlee Reservoir. The Lake Lowell portion is noted for concentrations of mallards and Canada geese and is an IBA for shorebirds and waterfowl. The river islands portion is an IBA for colonial waterbirds, waterfowl, and breeding ducks, geese, and shorebirds.

Notable other federal sites in the Treasure Valley-Owyhee Plateau include two long distance trails and an experimental watershed. Sites are are listed below.

Idaho Centennial Trail, Idaho, is a state-sponsored trail extending across mostly federal land from Nevada to Canada. In the Snake-Columbia shrub-steppe, the trail starts at Murphy Hot Springs on the East Fork Jarbridge River at the Nevada State Line (N42˚0’ W115˚19’), continues in the plateau above the Bruneau River, crosses the East Fork Bruneau at Winter Camp (N42˚33’ W115˚31’), passes a canyon lookout at N42˚42’ W115˚40’, crosses the Saylor Creek Range of Mountain Home Air Force Base, crosses the Snake River Birds of Prey area east of Bruneau, crosses the Snake River near Hammett (N42˚56’ W115˚32’), crosses the the Mount Bennett Hills (N43˚13’ W115˚19’), enters the Boise National Forest south of US Route 20, crosses US 20 at Packer Butte (N43˚17’ W115˚20’), and follows the Boise-Sawtooth National Forest boundary north into the Idaho Batholith.

Oregon Desert Trail, Oregon, is a 750-mile-long trail sponsored by the Oregon Natural Desert Association. It traverses mostly federal lands from Bend to Owyhee Reservoir. In the Owyhee Plateau area, the trail extends from US 95 at Blue Mountain Pass (N42˚19’ W117˚49’) east to the West Little Owyhee River, then follows the Owyhee River north to Lake Owyhee State Park (N43˚37’ W117˚14’).

Reynolds Creek Experimental Watershed (34), Northwest Watershed Research Center, Agricultural Research Service, Idaho (N43˚9’ W116˚46’) is in the Owyhee Mountains. This facility conducts long-term research in hydrology, water supply, seasonal snow, and landscape-scale processes related to fire and invasive weeds.

Cow Lakes (35), BLM, Oregon (N43˚6’ W117˚20’), are two lakes formed when the Jordan Crater lava flow blocked a stream. The lakes are an IBA for shorebirds and waterfowl.

Croy Creek Recreation Area (36), BLM, Idaho (N43˚29’ W114˚23’) is a mountain biking and hiking area west of Hailey. There are 20 miles of trails.

Gooding City of Rocks, BLM, Idaho (N43˚8’ W114˚46’) and Little City of Rocks, BLM, Idaho (N43˚7’ W114˚42’) are strange rock formations in the Mount Bennett Hills, on the north edge of the Snake River Plain off of State Route 46.

Jordan Crater (35), BLM, Oregon (N43˚8’ W117˚22’), is a 4,000-year-old caldera to the north of Upper Cow Lake. There are lava tubes, cones, domes, and cracks in the earth.

Jump Creek Canyon (36), BLM, Idaho (N43˚29’ W116˚56’), is a series of waterfalls in the Owyhee uplands south of Homedale.

Pillars of Rome (37), BLM, Oregon (N42˚51’ W117˚41’), are 100-foot-high cliffs overlooking the Owyhee River and stretching for five miles north of US Route 95 northeast of Burns Junction.

Silver City (38), BLM, Idaho (N43˚1’ W116˚44’), located in the Owyhee Uplands, is a partially restored 19th century mining town. In 1865, there were 250 mines extracting gold and silver from the area. Today there is a re-opened 1863 hotel and a BLM campground.

Notable state and local sites in the Treasure Valley-Owyhee Plateau area include the tallest sand dune in North America, important bird areas, and unusual geological formations, along with reservoir recreation areas.  Three Island Crossing State Park, Idaho (N42˚56’ W115˚20’), is described under Oregon National Historic Trail.

Balanced Rock County Park (39), Twin Falls County, Idaho ( N42˚32’ W114˚-57’), in the canyon of the Salmon Falls Creek west of Castleford, preserves a 48-foot-tall rock formation which balances on a pedestal three feet in width.

Boise Greenbelt (11), Idaho, is a 25-mile-long paved path along the Boise River from Garden City (N43˚38’ W116˚14’) upstream to Lucky Peak Dam (N43˚32’ W116˚4’).  It is an IBA for bald eagle, waterfowl, gull, and osprey.

Fort Boise Wildlife Management Area (23), Idaho ( N43˚49’ W117˚1’), is west of Parma at the confluence of the Boise, Owyhee, and Snake Rivers. Cottonwoods, willows and marsh provide habitat for snow geese and nesting teal and contains a cormorant rookery. Fort Boise is a site on the Oregon National Historic Trail. The site is an IBA for nesting waterfowl and shorebirds.

Boise River Wildlife Management Area (11), Idaho (N43˚34’ W116˚1’), is to the north and east of Lucky Peak Reservoir. This extensive area includes Lucky Peak, the Boise Front, Spring Shores, and Charcoal Creek watershed. It is a wintering area for mule deer, elk, and pronghorn. The area is also known for raptors.

Bruneau Dunes State Park (24), Idaho (N42˚54’ W115˚42’), protects a 470-foot- high dune, the tallest single-structured sand dune in North America. It is within the Snake River Birds of Prey NCA. A six-mile hiking trail and a separate equestrian trail encircle the dunes. The park also has an astronomical observatory.

Camas Prairie Centennial Marsh Wildlife Management Area, Idaho( N43˚16’ W115˚0’) is between Hill City and Fairfield and south of US 20. This area is noted for Camas lily (blue flowers). The marsh is an IBA, attracting waterfowl and shorebirds in the spring before it dries up in mid-July.

Celebration Park, Canyon County, Idaho (N43˚18’ W116˚31’), is a 700-acre county park noted for petroglyphs. A historic railroad bridge is maintained for pedestrian access to the south side of the river and hiking trails. The park is located on Can-Ada Road south from Melba to Victory Lane; proceed to the north bank of the Snake River.

Eagle Island State Park, Idaho (N43˚41’ W116˚24’) is three miles west of Eagle, Idaho, on an island in the Boise River and offers hiking and river recreation opportunities. A nearby blue heron rookery is an IBA.

Farewell Bend State Recreation Area (25), Oregon (N44˚18’ W117˚14’) is on Brownlee Reservoir at Exit 353 off I-84.  It is also an Oregon Trail site, with wagon ruts nearby.

Lucky Peak State Park (10), Idaho, is a three-unit reservoir recreation area is located on the U. S. Army Corps of Engineers’Lucky Peak Reservoir.  The Discovery and Sandy Point units (N43˚32’ W116˚4’) are downstream from the dam while the Spring Shores unit (N43˚36’ W115˚59’)  is on the upper end of the reservoir.

Lake Owyhee State Park (14), Oregon (N43˚37’ W117˚14’) is on the Bureau of Reclamation’s Owyhee Reservoir. Colorful volcanic rocks are a highlight of the site on a 53-mile-long lake.

Montour Wildlife Management Area (20), Idaho (N43˚56’ W116˚19’) is on the Payette River at the upper end of Black Canyon Reservoir. The Montour Valley is surrounded by mountains and is an area for waterfowl and upland game birds.

Ontario State Recreation Site (40), Oregon (N44˚3’ W116˚58’), is on the west bank of the Snake River at I-84 exit 374. This site on Route 201 provides birdwatching opportunities along the river.

Payette River Wildlife Management Area (1), Idaho (N 44˚0’ W116˚48’), is northeast of New Plymouth on the Payette River. It is a nesting area for hundreds of geese and ducks.

C.J. Strike Reservoir Wildlife Management Area, Idaho ( N42˚57’ W115˚59’) is owned by Idaho Power Company and managed as a state wildlife area. It is an IBA for attracting 100,000 waterfowl of 250 species, including passerines, curlew, owls, and pelicans. It is surrounded by Morley Nelson Snake River Birds of Prey NCA.

Succor Creek State Natural Area (41), Oregon (N43˚29’ W117˚8’), is a deep rocky canyon on the Idaho border. See description of Succor Creek flora in the introductory paragraphs.

Notable private sites in the Treasure Valley-Owyhee Plateau are Malheur Cave and Silver Creek Preserve. Malheur Cave (42), Robert Burns Masonic Lodge 97, Oregon (N43˚13’ W118˚20’) is a privately owned lava tube 3,000 feet long with an underground lake in the lower end. It is near the South Fork Malheur River and is used for outdoor meetings of the masons.  Silver Creek Preserve (43), The Nature Conservancy, Idaho ( N 43˚19’ W114˚9’) is an IBA west of Picabo in the Camas Prairie on US 20. It is a wetland area for trumpeter swan, waterfowl, wading birds, and warblers. Silver Creek is noted for fly fishing.


Graham, Alan.  2011. A Natural History of the New World: The Ecology and Evolution of Plants in the Americas. University of Chicago Press.

Sullivan, John. 2005. Resource Management Planning Efforts on the Bureau of Land Management’s Snake River Birds of Prey National Conservation Area, pages 1184-1185 IN Ralph, C. John, and Rich, Terrell D., editors. Bird Conservation Implementation and Integration in the Americas: Proceedings of the Third International Partners in Flight Conference, March 20-24, 2002, Asilomar, California, Volume 2.  Albany, CA: U.S. Dept. of Agriculture, Forest Service, Pacific Southwest Research Station.  USDA Forest Service General Technical Report PSW-GTR-191.