Gilpin County is the second-least extensive of the 64 counties of the U.S. state of Colorado, behind only the City and County of Broomfield. As of the 2010 census, the population was 5,441. The county seat is Central City. The county was formed in 1861, while Colorado was still a Territory, and was named after Colonel William Gilpin, the first Governor of the Territory of Colorado.
Gilpin County is part of the Denver-Aurora-Lakewood, CO Metropolitan Statistical Area.
According to the U.S. Census Bureau, the county has a total area of 150 square miles (390 km2), of which 150 square miles (390 km2) is land and 0.4 square miles (1.0 km2) (0.2%) is water. It is the second-smallest county by area in Colorado.