The Rapidan Dam is a concrete gravity dam located on the Blue Earth River in Rapidan Township southwest of Mankato, Minnesota in the United States. The dam was constructed from 1908 to 1910 to generate hydroelectric power. The dam and reservoir are owned by Blue Earth County, and the power plant and dam were operated by Eagle Creek Renewable Energy under an agreement with the county. Power was no longer generated at the dam due to damage from flooding in 2019 and 2020.