Mount Crested Butte is a home rule municipality in Gunnison County, Colorado, United States. Mount Crested Butte is the home of the Crested Butte Mountain Resort. The population was 801 at the 2010 census. ZIP code 81225 serves post office boxes for Mount Crested Butte and for neighboring Crested Butte; mail must be addressed to Crested Butte.