Delta is a home rule municipality that is the county seat and the most populous municipality of Delta County, Colorado, United States. The town population was 9,035 at the 2020 United States Census. The United States Forest Service headquarters of the Grand Mesa, Gunnison, and Uncompahgre National Forests are located in Delta.

Blue Mesa Reservoir is an artificial reservoir located on the upper reaches of the Gunnison River in Gunnison County, Colorado. The largest lake located entirely within the state, Blue Mesa Reservoir was created by the construction of Blue Mesa Dam, a 390 feet (120 m) tall earthen fill dam constructed on the Gunnison by the U.S. Bureau of Reclamation in 1966 for the generation of hydroelectric power. Managed as part of the Curecanti National Recreation Area, a unit of the National Park Service, Blue Mesa Reservoir is the largest lake trout and Kokanee salmon fishery in Colorado.