Eastern portion of Lake Alvin
|Location||Lincoln County, South Dakota|
|Primary inflows||Nine Mile Creek|
|Primary outflows||Nine Mile Creek|
|Basin countries||United States|
Lake Alvin is an artificial lake in Lincoln County, South Dakota between Harrisburg, South Dakota and Granite, Iowa. The lake is formed by a dam on Nine Mile Creek just before it enters the Big Sioux River, east of Harrisburg. It is part of a 59-acre (240,000 m2) recreational area.
Lake Alvin has always been a popular swimming location for those looking for a mid-sized beach. However, in 2005, the South Dakota GFP closed the swimming beach to the public due to high levels of fecal matter in the lake. A shutdown was again issued in 2009 for the same reason. Due to an extra rainy spring in both years, cow feces had been washed off a nearby farm in into the lake's tributaries, causing water to become dangerously unhealthy.
- "Lake Alvin Recreation Area". South Dakota Department of Game, Fish, and Parks. Retrieved 2009-11-07.