| Canyon Ferry Lake | |
|---|---|
 Canyon Ferry Lake | |
  Canyon Ferry Lake  Canyon Ferry Lake | |
| Location | Lewis and Clark and Broadwater Counties in  Montana, United States. Located near Helena, Montana. |
| Coordinates | 46°28′53″N 111°32′47″W / 46.481312°N 111.546404°W |
| Type | reservoir |
| Primary inflows | Missouri River |
| Primary outflows | Missouri River |
| Catchment area | 15,904 sq mi (41,190 km2) |
| Basin countries | United States |
| Max. length | 30 mi (48 km) |
| Max. width | 5 mi (8.0 km) |
| Surface area | 33,500 acres (13,600 ha) |
| Water volume | 2,051,000 acre⋅ft (2.530 km3) |
| Shore length1 | 76 mi (122 km) |
| Surface elevation | 3,797 ft (1,157 m) msl |
| Islands | Cemetery Island |
| Settlements | Canton and Townsend |
| 1 Shore length is not a well-defined measure. | |
Canyon Ferry Lake is a reservoir on the Missouri River near Helena, Montana and Townsend, Montana. It is Montana's third largest body of water, covering 35,181 acres (142 km2) and 76 miles (122 km) of shore (1). It was formed by the building of Canyon Ferry Dam, which was completed in 1954 and has been used for electricity, irrigation, and flood controls since.