Columbia Plateau (ecoregion)

The Columbia Plateau ecoregion is a Level III ecoregion designated by the United States Environmental Protection Agency (EPA) encompassing approximately 32,100 square miles (83,139 km2) of land within the U.S. states of Washington, Oregon, and Idaho. The ecoregion extends across a wide swath of the Columbia River Basin from The Dalles, Oregon to Lewiston, Idaho to Okanogan, Washington near the Canada–U.S. border.

Source: Wikipedia — Columbia Plateau (ecoregion) (CC BY-SA 4.0)