Gunnison is a home rule municipality that is the county seat and the most populous municipality of Gunnison County, Colorado. The city population was 6,560 at the 2020 United States Census. The city was named in honor of John W. Gunnison, a United States Army officer who surveyed for a transcontinental railroad in 1853. Gunnison is a college town, home to Western Colorado University, the oldest university in Colorado's Western Slope region.