Lake Springfield Lake Springfield is a 4,200-acre reservoir on the southeast edge of Springfield, Illinois, with about 57 miles of shoreline. Built in the 1930s by damming Sugar Creek, it provides drinking water and power-plant cooling for the city while also serving as one of central Illinois’ most popular recreation areas. The lake is ringed by public parks, boat launches, and more than 700 private homes and docks. Visitors come for boating, sailing, fishing, and picnicking, with largemouth bass, catfish, crappie, and bluegill among the most sought-after fish. Designated areas allow swimming and no-wake boating..