Canyon Ferry Dam, Hydroelectric power station and gravity dam in Lewis and Clark County, Montana.

Canyon Ferry Dam is a 69 m (225 ft) high concrete gravity dam, 305 m (1,000 ft) long, with a crest 6 m (20 ft) thick and a base 53 m (173 ft) thick. Its spillway is controlled by four radial gates, and the adjacent power plant houses three 16.5 MW Francis turbine generators. The dam impounds Canyon Ferry Lake on the Missouri River.

The first Canyon Ferry Dam was a timber crib structure with rock fill, built between 1896 and 1898 by the Helena Water and Electric Power Company 1.5 miles upstream; it stood 29 feet high and 485 feet long. The present concrete gravity dam was built as the Canyon Ferry Unit of the Pick-Sloan Plan, approved by the Flood Control Act of 1944, with construction from May 24, 1949 to June 23, 1954. Its first generator went online on December 18, 1953, and the other two in 1954.

The reservoir is named after the Canyon Ferry crossing, a Missouri River ford used by prospectors during the 1860s Montana gold rush. The dam's reservoir, Canyon Ferry Lake, now covers the site of the old crossing and the original 1898 timber dam, which lies submerged about 1.5 miles upstream.

The dam sits about 20 miles east of Helena, reached via Montana Highway 284 along the reservoir's western shore. The crest is 20 ft wide and the base 173 ft, so the structure is best viewed from downstream. The spillway's four radial gates release up to 150,000 cu ft/s.

The original 1896–1898 dam, a timber crib structure with rock fill, stood 1.5 miles upstream and was only 29 feet high and 485 feet long. The present dam's spillway is controlled by four radial gates and can discharge up to 150,000 cubic feet per second.