The county in which Sun River Montana is located is ranked as the what most populous county in Montana?
Cascade County, Montana Cascade County ("cascade" means "waterfall" in French) is a county located in the U.S. state of Montana. As of the 2010 census, the population was 81,327, making it the fifth-most populous county in Montana. Its county seat is Great Falls.
Clark County, Washington Clark County is a county in the southwestern part of the U.S. state of Washington. As of the 2010 census, the population was 425,363, making it Washington's fifth-most populous county. Its county seat and largest city is Vancouver. It was the first county in Washington, named after William Clark of the Lewis and Clark Expedition. It was created by the provisional government of Oregon Territory on August 20, 1845, and at that time covered the entire present-day state.