Snowmass (sometimes known locally as Old Snowmass) is an unincorporated town and a U.S. Post Office located in Pitkin County, Colorado, United States. It is situated in the valley of the Roaring Fork River, near the mouth of Snowmass Creek along State Highway 82 between Aspen and Basalt. It consists largely of a post office, several commercial businesses, and surrounding houses and ranches. The Snowmass Post Office has the ZIP Code 81654.