Lake County is a county located in the U.S. state of Colorado. As of the 2020 census, the population was 7,436. The county seat and the only municipality in the county is Leadville. The highest natural point in Colorado and the entire Rocky Mountains is the summit of Mount Elbert in Lake County at 14,440 feet elevation.

Leadville is a statutory city that is the county seat, the most populous community, and the only incorporated municipality in Lake County, Colorado, United States. The city population was 2,633 at the 2020 census. It is situated at an elevation of 10,158 feet (3,096 m). Leadville is the highest incorporated city in the United States and is surrounded by two of the tallest peaks in the state.