Snowmass (sometimes known locally as Old Snowmass) is an unincorporated community and a U.S. Post Office in Pitkin County, Colorado, United States. It is in the valley of the Roaring Fork River, near the mouth of Snowmass Creek. It is on 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.