|Location||Douglas / Jefferson counties, Colorado, United States|
|Primary inflows||South Platte River|
|Primary outflows||South Platte River|
|Catchment area||3,000 sq mi (7,800 km2)|
|Basin countries||United States|
|Surface area||1,500 acres (610 ha)|
|Max. depth||47 m (154 ft)|
Chatfield Reservoir and dam on the South Platte River south of Littleton, Colorado were built by the United States Army Corps of Engineers as a response to the disastrous flood of 1965. In addition to its primary purpose of flood control, it serves as one of many water supply reservoirs for the city of Denver, Colorado. In 1966, the U.S. Atomic Energy Commission projected a total federal cost of $74 million. Construction of the project was begun in 1967 and the dam was completed in 1975.
The massive breastworks of the dam measure approximately 13,136 feet (4,004 m) in length with a maximum height of the dam of 147 feet (45 m) above the streambed. The normal depth of the lake is 47 feet (14 m) at its deepest point. This means the dam towers 100 feet (30 m) above the mean surface of the reservoir.
The lake drains an area of more than 3,000 square miles (8,000 km2). The 1,500 acre (6 km2) lake has a conservation storage capacity of 27,000 acre·ft (0.033 km3) with a flood-control pool of over 350,000 acre·ft (0.43 km3)
The reservoir is surrounded by Chatfield State Park, a recreation area with boating, horseback riding and camping. A secondary inflow from the south is Plum Creek. A tertiary inflow from the west is Deer Creek.
There are 212 bird species that are frequently found at Chatfield Reservoir. These birds either permanently live there or just go there to rest after long migrations. There is a Chatfield bird watch list that anyone can access. The bald eagle, white pelican and burrowing owl have been seen.