The federal government authorized the Buford Dam multipurpose project in 1946 as part of the larger Apalachicola-Chattahoochee-Flint river system. Construction activity began in the early 1950s; current USACE sources give slightly different milestone years, with the 2022 master plan describing construction as beginning in 1954 and completing in 1957 while the Mobile District hydropower page gives 1951 through 1956. Lake Monkey preserves that source difference instead of forcing one timeline where the agency itself publishes two.
Congress officially designated the reservoir Lake Sidney Lanier on March 29, 1956. Buford Dam impounded the Chattahoochee River northeast of Atlanta, with the Chestatee River also feeding the new lake. The power plant came online in 1958 and today has a listed generating capacity of 126 megawatts.
Lake Lanier was never a single-purpose recreation lake. USACE's current master plan describes a project authorized for hydropower, flood-risk management, navigation support, water supply, water quality, fish and wildlife conservation, and recreation. Those overlapping purposes explain why lake level, downstream releases, Atlanta-area water supply and recreation all intersect in modern lake management.
Over time Lake Lanier became one of the Corps' most heavily visited projects. USACE currently describes it as the most-visited U.S. Army Corps of Engineers project and reports millions of visitors each year. The reservoir now combines a major sport fishery, marinas, campgrounds, public ramps and large tournament facilities with active federal water-management and hydropower infrastructure.