Pitkin County is one of the 64 counties in the U.S. state of Colorado. As of the 2010 census, the population was 17,148. The county seat is Aspen. The county is named in honor of the late Colorado Governor Frederick Walker Pitkin. Pitkin County has the fourth highest per-capita income of any county in the United States.Pitkin County is included in the Glenwood Springs, CO Micropolitan Statistical Area, which is also included in the Edwards-Glenwood Springs, CO Combined Statistical Area.