Palouse Falls, on the Palouse River in southeast Washington, is one of the state’s most striking natural landmarks and a vivid window into the Columbia Plateau’s geologic past. Within Palouse Falls State Park, the river descends in two stages to a total drop of about 200 feet, cutting a canyon 377 feet deep through basalt. The falls and surrounding coulees, plunge pools, potholes, buttes, and pinnacles were shaped by repeated Missoula floods during the Pleistocene, which diverted the ancestral Palouse into a new channel to the Snake River. Protected since 1951, the site also reflects regional history and later efforts to preserve it from dam construction.