The first white settlers in the area of Chatfield went in search of gold in 1858. Prospectors discovered gold in the vicinity of Cherry Creek and the South Platte River. When these pioneers began to build the settlement that is Denver, Indians warned them that settling in the area was "bad medicine".
In 1870, Isaac W. Chatfield, a Lieutenant of the Union in the Civil War, bought land at the confluence of the South Platte River and Plum Creek. Chatfield farmed the land until his departure in 1879, and both the area and the nearby road still bear his name.
The area continued to grow as an agricultural community, and center of activity and housing. The warning of "bad medicine" turned out to be true, with floods along the South Platte River corridor through Denver in 1933, 1935 and 1942.
On June 16, 1965, the flow of the South Platte River had overgrown its banks from the significant rain in the area. The torrents of water flowed north through Denver wiping out bridges, homes, and businesses. After the flood the official decision was made by State and Federal authorities to build Chatfield Dam as flood control.
In August 1967, two years after the flood, the Army Corps of Engineers began the construction of the project with a budget of 85 million dollars. Work in the recreational area of 5600 acres began in 1973, and in 1974 the State Parks of Colorado began a 25 year lease to manage the area. The dam and reservoir with recreation area opened to visitors in 1975.