Lake Alvin is a compact yet popular 105-acre artificial impoundment located approximately 5 miles east and half a mile north of Harrisburg, South Dakota. Named for Alvin Dempewolf, the only World War I soldier from Harrisburg who died overseas, this reservoir was created by damming Nine Mile Creek, with construction completed in August 1954 and the lake reaching full capacity in 1957. Despite its small size, Lake Alvin has become a regional fishing destination, managed primarily as a walleye and black crappie fishery while offering additional angling opportunities for various warmwater species. The lake features a maximum depth of 26 feet with a mean depth of 9 feet and operates under no-wake zone restrictions to protect the shoreline from erosion.