Bagnell Dam (informally, the Osage Dam) impounds the Osage River in the U.S. state of Missouri, creating the Lake of the Ozarks. The dam is located in the city of Lakeside in Miller County, near the Camden-Miller County line. The tall concrete gravity dam was built by the Union Electric Company (now Ameren) to generate hydroelectric power at its Osage Powerplant. It is long, including a long spillway and a long power station. The facility with eight generators has a maximum capacity of 215 megawatts.