Keystone is an unincorporated community and a census-designated place (CDP) located in and governed by Summit County, Colorado, United States. The CDP is a part of the Breckenridge, CO Micropolitan Statistical Area. The population of the Keystone CDP was 1,079 at the United States Census 2010. The Dillon post office (Zip Code 80435) serves Keystone postal addresses. The Keystone CDP includes the Keystone Resort and Keystone village.
The Keystone CDP has an area of 26,518 acres (107.316 km2), including 21 acres (0.086 km2) of water.