Lucky Peak Dam

Lucky Peak Dam is a rolled earth and gravel fill embankment dam in the western United States, located on the Boise River in southwestern Idaho. In Ada County east of Boise, it is directly downstream of Arrowrock Dam, a concrete arch dam completed in 1915. At the time of its construction in the early 1950s, Lucky Peak's primary purpose was flood control, with a secondary purpose of irrigation. The normal operating elevation of the full reservoir is 3055 ft above sea level, the empty reservoir's elevation (Boise River) is 2824 ft.

Construction began in November 1949 by the U.S. Army Corps of Engineers. Most of the federal dams in southern Idaho, including the others on the Boise River, were built by the Bureau of Reclamation, not the Corps of Engineers. The Idaho Power Company, a private utility, built multiple hydroelectric dams on the Snake River.

Located along State Highway 21, 10 mi upstream from the city of Boise, it was built without hydroelectric power generation. Construction of the powerhouse began in 1984 and it became operational in 1988, generating electricity primarily for Seattle City Light.

The dam was named after a nearby mountain in the Boise Range, about 4 mi north of the dam (43.605°N, -116.062°W). The summit elevation of Lucky Peak mountain (a.k.a. Shaw Mountain) is 5904 ft.

The dam forms Lucky Peak Lake and is surrounded by Lucky Peak State Park.

The dam is also in close proximity to the Lucky Peak Dam Zeolite Occurrence.