Keystone is a home rule town located in Summit County, Colorado, United States. The town is a part of the Breckenridge, CO Micropolitan Statistical Area. Keystone residents voted to incorporate on March 28, 2023, becoming a municipality on February 8, 2024. The municipality includes the Keystone Resort and Keystone Village. The population of the former Keystone census-designated place (CDP) was 1,369 at the United States Census 2020. However, the boundary of the current municipality encompasses a smaller geographic area than the boundary of the former CDP; as of 2022 the population of the municipality was estimated to be 995. The Dillon post office (Zip Code 80435) serves Keystone postal addresses.