The county in which Sun River Montana is located is ranked as the what most populous county in Montana?
Sun River, Montana Sun River is a census-designated place (CDP) in Cascade County, Montana, United States. The population was 124 at the 2010 census. It is part of the Great Falls, Montana Metropolitan Statistical Area.
Jefferson County, Colorado Jefferson County (Jeffco) is one of the 64 counties in the U.S. state of Colorado. As of the 2010 census, the population was 534,543, making it the fourth-most populous county in Colorado. The county seat is Golden, and the most populous city is Lakewood.