Zumwalt Prairie, National Natural Landmark grassland in Wallowa County, US

Zumwalt Prairie is a 330,000-acre grassland on a basalt plateau in Wallowa County, northeastern Oregon, rising from 3,500 to 5,500 feet along the west edge of Hells Canyon. It is dominated by native bunchgrasses such as Idaho fescue, bluebunch wheatgrass and Sandberg's bluegrass, along with many wildflowers.

This land served as home and hunting grounds for the Chief Joseph band of the Nez Perce until Euro-American settlers arrived in the 1850s. Their arrival led to the displacement of the Native American tribes from these territories.

The prairie takes its name from the unincorporated town of Zumwalt, which received a post office in 1903; it closed in 1936 and the town is now a ghost town. The Nature Conservancy has owned its 36,000-acre preserve since 2000 and holds a conservation easement on the 12,000-acre Lightning Creek Ranch.

Access is via gravel roads from the towns of Joseph or Enterprise; the prairie lies along the west rim of Hells Canyon on the Oregon-Idaho border. The Nature Conservancy's 36,000-acre preserve is the main protected tract, and the 4,400-acre National Natural Landmark lies within it. Summer days average 84 °F while winter nights drop to about 16 °F, and most rain and snow falls in winter.

The prairie escaped the plow largely because of its high elevation, harsh climate and poor soils, so its native bunchgrass habitat survived while most North American prairies were converted. More than 100 bee species have been recorded here, pollinating the wildflowers and grasses.