The City of Aspen is a Home Rule Municipality that is the county seat and the most populous city of Pitkin County, Colorado, United States. The United States Census Bureau estimates that the city population was 5,804 in 2005.

Founded as a mining camp in the Colorado Silver Boom and named because of the abundance of aspen trees in the area, the city is now a ski resort and an upscale tourist center.

In the late 20th century the city developed as an off-beat haven for celebrities, attracting such people as John Denver (who wrote several folk songs about the town, including "Aspenglow", and "Starwood in Aspen") Michael Douglas and Hunter S. Thompson.