Palouse Grasslands, Part I

The Palouse grasslands (NA813) as delineated by the World Wildlife Fund and Nature Conservancy include portions of Idaho, Oregon, and Washington which are in the rain shadow of the Cascades. This description also includes the Okanagan Valley of British Columbia because of its grassland habitat extending north from the US-Canada border. The ecoregion is characterized by native bluebunch wheatgrass and Idaho fescue with scattered shrubs. The habitat is maintained by fire. Locations within the Palouse grasslands are described below. Many areas have been extensively modified by agriculture; the agricultural landscape is characterized by yellow rapeseed flowers in the spring. Cities in the habitat include Osoyoos, British Columbia; Cheney, Chelan, Okanogan, Pullman, and Walla Walla, Washington; Moscow and Lewiston, Idaho; and Pendleton, Oregon.

The areas of the Palouse grasslands between Spokane and Grand Coulee are part of the Channeled Scablands, an unusual landscape of scour channels called coulees and dry river valleys that once carried tremendous amounts of water. The idea that these features were created during a catastrophic flood was first proposed during the 1920s by J. Harlen Bretz. His proposals were met with skepticism until the source of the flood, a failed ice dam at glacial Lake Missoula, was confirmed at a meeting of the American Association for the Advancement of Science in the 1940s (Baker 1978). Other evidence of glaciation is evident in the Palouse grasslands at Boulder Park and Sims Corner National Natural Landmarks described below.

There is one National Historic Landmark in the Palouse grasslands ecoregion. Marmes Rockshelter, Washington (N46˚35’ W118˚13’), is at the confluence of the Snake and Palouse Rivers, but is now submerged by Lower Monumental Reservoir.  The site provides evidence of human occupation for over 8,000 years and contains the oldest human remains excavated in the New World, at 11,000 years BP. Also found at the site was a Jefferson Peace Medal, evidence of contact with the Lewis and Clark expedition.

There are 13 National Natural Landmarks in the Palouse grasslands ecoregion.

Boulder Park and McNeil Canyon Haystack Rocks, Washington (N47˚53’ W119˚48’ (Boulder Park) and N47˚50’ W119˚54’ (McNeil Canyon)) have the greatest concentration of glacial erratics in the Columbia Plateau. The two sites are east of Chelan and east of the Columbia River on the Waterville Plateau.  McNeil Canyon is on the east side of the Columbia River north of the US Route 97 crossing.  Boulder Park is seven miles west of Mansfield, then four miles north of Route 172.

Davis Canyon Natural Area Preserve, Washington (N48˚15’ W119˚46’) is a 415-acre site and the largest and least disturbed antelope bitterbrush-Idaho fescue community known.  It is located south of Okanogan and west of the Okanogan River.

Grand Coulee, Washington, is between the town of Grand Coulee (N47˚56’ W119˚1’) on the Columbia River and Soap Lake (N47˚24’ W119˚30’). This 50-mile-long ice age flood channel was carved by the periodic floods originating from Lake Missoula. Perhaps a highlight of the steep-sided channel is the dramatic Dry Falls (N47˚36’ W119˚21’)), a 400-foot dry waterfall 3.5 miles wide, now in Sun Lakes/Dry Falls State Park. Also occupying Grand Coulee upstream of Dry Falls is Banks Lake/Dry Falls Dam (N47˚37’ W119˚19’), a Bureau of Reclamation irrigation storage facility within the Columbia Project, and Steamboat Rock State Park (N47˚52’ W119˚8’), a steep-sided mountain surrounded by the flood channel.

Grande Ronde Feeder Dikes, Washington (N46˚3’ W117˚15’), are examples of the basalt dikes which fed the Columbia flood basalt event during a plate boundary collision. The privately owned site is at State Route 129 at the Grande Ronde River.

Grande Ronde Goosenecks, Bureau of Land Management (BLM) Grande Ronde Area of Critical Environmental Concern and Chief Joseph Wildlife Management Area, Washington (N46˚3’ W117˚1’), illustrate the regional uplift of the Columbia Plateau, with stream entrenchment into the uplifted area. In this area, extreme elevation changes range from less than 1,000 feet to more than 4,000 feet, with a 1,500-foot-deep canyon along the lower Grande Ronde River.

Kahlotus Ridgetop Natural Area Preserve, Washington (N46˚42’ W118˚34’), is four miles north of Kahlotus off State Route 21.  This 240-acre native prairie remnant is the best remaining example of Palouse prairie grassland.

Lawrence Memorial Grassland Preserve, The Nature Conservancy, Oregon (N44˚57’ W120˚48’) is three miles southwest of Shaniko off State Route 218; this area has peculiar biscuit-shaped mounds 10 to 20 m wide and 100-120 cm high. There are undisturbed grasslands of bunchgrass with sagebrush.

Rose Creek Preserve, Palouse-Clearwater Environmental Institute, Washington (N46˚50’ W117˚13’), is on Shawnee Road northeast of Albion and is the best remaining example of aspen-black hawthorne-cow parsnip habitat in the Columbia Plateau.

Sims Corner Eskers and Kame Complex, Washington (N45˚50’ W119˚22), are at the junction of Routes 17 and 172 north of Coulee City. Numerous glacial features are evident, including scattered glacial erratics, eskers, and kames.  Glacial erratics are boulders which rode on top of the ice and are out of place compared to the surrounding geology.  Eskers are long winding ridges which formed in streams under glaciers. Kames are irregularly shaped hills formed by retreating glaciers. Route 172 heading west from Sims Corner passes several eskers, the Pot Hills, and Yeager Rock, a 20-foot high glacial erratic just east of Mansfield.

Steptoe Butte State Park, Washington (N47º2’ W117º18’) and Kamiak Butte County Park, Whitman County, Washington (N46º52’ W117º10’) are quartzite outliers of the Coeur d’Alene Mountains in the Palouse Prairie. Both mountains rise more than 1,000 feet above the surrounding terrain and provide 200-mile vistas. The Pine Ridge National Recreation Trail encircles Kamiak Butte.

Withrow Moraine and Jameson Lake Drumlin Field, Washington (N47˚41’ W119˚37’), are on the 4,000-acre Nature Conservancy Moses Coulee Preserve. Withrow Moraine is the terminal lobe and debris deposit of the Okanagon Glacier which blocked Moses Coulee, forcing the Columbia River to form the Grand Coulee. Under the glacier were the egg-shaped grooved hills called drumlins, which are visible to the east of Jameson Lake. The Dutch Henry Falls hiking trail (N47˚39’ W119˚40’) goes by a 200-foot wall of rocks, part of the Withrow Moraine. Dutch Henry Falls is north of US Route 2 in the Moses Coulee. South of US Route 2 is McCartney Creek Meadows (N47˚30’ W119˚44’), also on the preserve. The preserve is home to the pygmy rabbit, spotted bat, and 14 of the 15 bat species that inhabit Washington. Moses Coulee is an IBA for songbird migration.

Zumwalt Prairie Preserve, The Nature Conservancy, Oregon (N45˚33’ W116˚55’), is a 33,000-acre property, 4,000 acres of which were designated a national natural landmark. Elevations range from 2,000 to 5,500 feet on the largest remaining intact bunchgrass prairie in North America. Four trails have been developed for access, and Duckett Road (County Road 676) provides a ten-mile drive from high elevation prairie to the canyon near Imnaha. Trails are Horned Lark Trail off of Zumwalt-Buckhorn Road (County Road 697 north of State Route 82 at Enterprise); and Patti’s Trail, Harsin Butte Trail, and Canyon Vista Trail, all off of Duckett Road.

The National Forest System in the Palouse grasslands includes two national forests and the Hells Canyon National Recreation Area (NRA), Idaho-Oregon, which is 652,000 acres. The Dug Bar site of the Nez Perce NHP (see) is located on the Snake River within the NRA. It is accessible by following the Imnaha River Road north (downstream) through the NRA from Imnaha. Imnaha River is a wild and scenic river for 60 miles in the national recreation area from the Eagle Cap Wilderness (N45˚6’ W117˚4’) downstream to the Snake River (N45˚49’ W116˚46’). Its elevation drop is more than 7,000 feet. The Imnaha River Road (Forest Road 3955) follows the Imnaha River upstream to the Hells Canyon Scenic Byway. Basin Creek RNA (N45˚40’ W116˚49’) is a 400-acre area near the Imnaha River with Idaho fescue and bluebunch wheatgrass plant communities. Hat Point Road (Forest Road 4240) climbs from the Imnaha River (N45˚33’ W116˚49’) up the cliffs of Grizzly Ridge to Saddle Creek Overlook and on to Hat Point (N45˚26’ W116˚40’) for one of the most spectacular views. It is a one-lane unpaved road. Buckhorn Overlook (N45˚45’ W116˚49’) and Cache Creek Ranch on the Snake River (N45˚59’ W116˚54’) are also in the Palouse Prairie portion of the NRA.

Wallowa NF, Oregon, is 995,000 acres, administered together with the Whitman NF. Much of the eastern portion is part of the Hells Canyon NRA (see separate description). Joseph Creek is a wild and scenic river for nine miles from Joseph Creek Ranch (N45˚48’ W117˚11’) downstream to the Wallowa NF boundary (N45˚52’ W117˚15’). It is a 2,000-foot-deep canyon with exposed rimrock. To the east of Joseph Creek is Haystack Rock RNA (N45˚53’ W117˚13’), which is 425 acres with Idaho fescue, bluebunch wheatgrass, and Talus garland plant communities. Also to the east of Joseph Creek is Horse Pasture Ridge RNA (N45˚53’ W117˚12’), 340 acres with Idaho fescue and bunchgrass plant communities. The Joseph Canyon Viewpoint (N45˚50’ W117˚16’), a site of the Nez Perce National Historical Park, is located on State Route 3 south of the Washington State Line. The deep canyon to the east of Route 3 is Swamp Creek, which contains outstanding scenery from its confluence with Joseph Creek (N45˚49’ W117˚4’) upstream to the forest boundary (N45˚36’ W117˚13’). To the southeast, Vance Knoll RNA (N45˚42’ W116˚57’) is 190 acres of scabland with a Sandberg’s bluegrass/one-spike oatgrass plant community.

The southeastern portion of the forest is mostly the watershed of Big Sheep Creek, which is eligible for the national wild and scenic river system from the Eagle Cap Wilderness boundary (N45˚11’ W117˚6’) to the Imnaha River confluence (N45˚33’ W116˚50’).

Wenatchee NF, Washington, includes lower slopes of the eastern Cascades that include grasslands along the Columbia River. The Thompson Clover RNA (N47˚34’ W120˚18’) is just north of Rocky Reach Dam/Lake Entiat in Swakane Canyon and includes a rare species of clover on grassy hillsides below ponderosa pine woodland.

The National Park System in the Palouse grasslands ecoregion includes four parks, of which one is paleontological, two are historic, and one is a national recreation area. John Day Fossil Beds National Monument, Oregon, consists of three units, which together provide the most complete record of terrestrial land mammal evolution in the northern Hemisphere extending over 44 million years. One unit is in the Palouse Prairie ecoregion. Clarno Unit (N44˚55’ W120˚25’) is 2,000 acres on State Route 218 between the towns of Antelope and Fossil. It features trails leading to an arch and petrified wood and is known for 150-foot-high rock formations overlooking the area called The Palisades. The Clarno Nut Beds contain 175 species of trees, shrubs, and trees from a tropical forest that lived 44 million years ago. Clarno is also the most species-rich petrified wood area in the world, and fossil panthers, horses, crocodiles have been found. The Hancock Mammal Quarry (40 million years old) contains fossil horses, brontotheres, and bear-like mammals. The Oregon Museum of Science and Industry operates Hancock Field Station (N44˚55’ W120˚26’) as a private inholding in the Clarno Unit. It is used for school field trips and as an educational camp.

Nez Perce National Historical Park, Idaho-Montana-Oregon-Washington, consists of sites commemorating the stories, events, and artifacts of the Nez Perce Tribe. Of the 38 sites comprising the park, 22 are in the Palouse Prairie:

  • Ant and Yellowjacket, Idaho (N46˚27’ W116˚51’), commemorates a story about an argument between Ant and Yellowjacket which resulted in them being turned into a stone arch. The site is nine miles east of Lewiston on US Route 12.
  • Buffalo Eddy, Washington (N46˚11’ W116˚57’) is 15 miles south of Asotin on the Snake River and is the site of petroglyphs dating to 4,500 before present.
  • Camas Prairie, Idaho (N45˚55’ W116˚14’) is south of Grangeville on US Route 95.  This was a root gathering area for the Nez Perce tribe.
  • Confluence Overlook, Idaho (N46˚27’ W117˚1’) is at the top of Lewiston Hill on US 95. It provides an overlook of a trading post site at the confluence of the Clearwater and Snake Rivers.
  • Canoe Camp, Idaho (N46˚30’ W116˚20’), at the confluence of the North Fork Clearwater and Clearwater, was where the Lewis and Clark expedition built canoes for travel to the Pacific Ocean in 1805. The site is four miles west of Orofino on US Route 12.
  • Clearwater Battlefield, Idaho (N46˚5’ W115˚59’), on State Route 13 south of Stites,  is the site of an 1877 attempt to engage the Nez Perce, but the tribe withdrew.
  • Cottonwood Skirmishes, Idaho (N46˚1’ W116˚20’), took place two miles south of Cottonwood on US Route 95. This was the site of additional hostility between the US Army and the Nez Perce after the White Bird Battle.
  • Coyote’s Fishnet, Idaho (N46˚27’ W116˚53’) is a group of rock formations on US 95-12 seven miles east of Lewiston which commemorates a story about an argument between Coyote and Black Bear.
  • Craig Donation Land Claim, Idaho (N46˚21’ W116˚46’) is located on US Route 95 south of Lapwai. William Craig was a mountain man and the first Euro-American settler in Idaho. In 1840, he settled in the Lapwai Valley. He was an interpreter in the negotiations that led to the establishment of the Nez Perce Reservation, and as a result he was allowed to keep his homestead.
  • Dug Bar, Oregon (N45˚48’ W116˚41’), is on the Snake River in Hells Canyon National Recreation Area and Snake Wild and Scenic River. The site is best accessed by boat, but there is a road from the Imnaha River that can be driven by high clearance vehicle. Tribal members who lived in Oregon crossed the Snake River here in 1877 on their way to the reservation in Idaho. The crossing was in the spring when the water was high, making the crossing more hazardous than usual and resulting in the loss of cattle.
  • Hasotino Village, Lower Granite Reservoir, Idaho (N46˚21’ W117˚3’) is an 11,000-year-old prehistoric village site used for lamprey fishing.
  • Fort Lapwai and Northern Idaho Indian Agency, Idaho (N46˚24’ W116˚49’) are on US Route 95 south of Spalding. This is the location of an 1862 US Army fort and the agency set up to administer the treaties with the tribes in the area.
  • Lenore, Idaho (N46˚31’ W116˚37’) is on US Route 12 about 25 miles east of Lewiston and is the site of a prehistoric Nez Perce village with pit houses.
  • Lostine Campsite, Oregon (N45˚33’ W117˚29’) is at the junction of the Lostine and Wallowa Rivers near Wallowa. This is a traditional Nez Perce summer campsite where Old Chief Joseph died in 1871.
  • Nez Perce Cemetery and Nez Perce Campsites, Washington (N48˚10’ W118˚59’), are in Nespelem on the Colville Reservation and not publicly accessible. The graves of Chief Joseph the Younger and other participants in the war of 1877 are here. They moved here after exile in Oklahoma.
  • Old Chief Joseph’s Gravesite, Oregon (N45˚20’ W117˚13’) is in a cemetery on State Route 82 near Wallowa Lake dam. The father of Chief Joseph was reburied here in 1926 among other Nez Perce graves. He signed the original treaty of 1855 but refused to sign other treaties and compelled his son, Chief Joseph, to never agree to sell the homeland.
  • St. Joseph’s Mission, Idaho (N46˚19’ W116˚43’) is located on Mission Creek Road off US 95 west of Culdesac. This was a Catholic mission to the Nez Perce, established in 1874 on the reservation.
  • Spalding, Idaho (N46˚27’ W116˚49’), is the site of the 1836 Spalding Presbyterian Mission to the Nez Perce, as well as cemeteries, a church, and general store associated with the town of Spalding. The village site at the confluence of Lapwai Creek and the Clearwater River has been occupied for as much as 10,000 years. The park visitor center is located at this site, which is on US 95 about 11 miles east of Lewiston.
  • Tolo Lake, Idaho (N45˚55’ W116˚14’) is the site of Tepahlewah, an ancient council ground. In 1877, bands forced to leave Oregon congregated here before moving onto the reservation to the north. In 1994, fossil mammoths were found in lake sediments. The site is west of Grangeville on the Camas Prairie.
  • Weis Rockshelter, Idaho (N45˚57’ W116˚22’), is the site of an 8,000-year-old prehistoric habitation in Rocky Canyon, used up until 600 years ago.
  • White Bird Battlefield, Idaho (N45˚47’ W116˚7’) is south of Grangeville on US Route 95.  In 1877, this was the first battle of the Nez Perce War, resulting in a defeat of the US Calvary and the beginning of the ultimately unsuccessful flight to Canada. Following the battle, the Nez Perce attempted to make it to the Lolo Trail over the mountains; some skirmishes were fought south of Cottonwood on US Route 95 at the Cottonwood Skirmishes (N46˚1’ W116˚20’).

Lake Roosevelt National Recreation Area, Washington, which includes a strip of reservoir lands between elevations 1290 and 1310 along the Columbia River impounded by Grand Coulee Dam, extends into the Palouse Prairie ecoregion between Grand Coulee Dam (N47˚57’ W118˚59’) and Fort Spokane (N47˚54’ W118˚18’) on the Columbia River and between Fort Spokane and Little Falls Dam (N47˚50’ W117˚55’) on the Spokane River. The lands on the north side of the Spokane River fronting the Spokane Indian Reservation are not part of the NRA; neither are the lands of the Colville Indian Reservation on the north side of the Columbia River. The portion of the NRA in the Palouse Prairie ecoregion includes Fort Spokane, Spring Canyon-Bunchgrass Prairie Nature Trail, and the Grand Coulee Dam area. Fort Spokane is a western military frontier fort operated between 1880 and 1898. At Fort Spokane is a 1.6-mile interpretive trail. Spring Canyon (N47˚56’ W118˚56’) is an ice age flood area.

Whitman Mission National Historic Site, Washington (N46˚2’ W118˚28’) was established to commemorate the 1847 killing of missionaries by the Cayuse Tribe. The mission was established in 1836 but is believed to have had little success in converting tribal members. It later became a site on the Oregon Trail. It was burned in 1848 during the ensuing war between the settlers and the tribe. The 100-acre park includes the foundations of mission buildings and Oregon Trail ruts and is seven miles west of Walla Walla. The mission is not on the main National Historic Trail route but is related to the trail because the Whitmans assisted the first emigrants and helped blaze the main trail.


Baker,  Victor R. 1978. The Spokane Flood Controversy and the Martian Outflow Channels. Science 202:1249-1256.

to be continued