East River Electric Power Cooperative
121 1st St SE, Madison, South Dakota, United States

East River Electric Power Cooperative is a wholesale electric power supply cooperative serving 24 rural electric cooperatives and one municipally-owned electric system, which in turn serve more than 92,000 homes and businesses and about 250,000 consumers.Our 40,000 square mile service area covers the rural areas of 41 counties in eastern South Dakota and 22 counties in western Minnesota.

East River Electric Power Cooperative was organized in October 1949 in Sioux Falls, South Dakota. The cooperative established its headquarters in Madison, SD in November 1950, and Virgil Hanlon was named the first general manager. Headquarters was officially moved to Madison in 1951. Later that year, East River was awarded its first transmission construction loan to build the first 69 kV system in eastern South Dakota.In 1954, the first hydropower from Fort Randall Dam flowed to East River at the Armour and Wagner substations. In 1961, East River joined Basin Electric Power cooperative. Five years later Basin’s first generating plant, Leland Olds Unit 1, began operations. Later that year the city of Elk Point became the first municipal electric system to join East River.East River joined as one of the founders of the Touchstone Energy program and served as one of the test markets for the branding image program in 1998.Two years later East River and its member systems provided leadership to establish the Value-Added Agriculture Development Center.