Pierce Lake is a 162-acre reservoir located within Rock Cut State Park in Winnebago County, Illinois, situated between the towns of Machesney Park and Caledonia along Route 173. This artificial impoundment was created from a former rock quarry, with the lake beginning to fill on May 15, 1961. The lake covers terrain where much of the lower end was cut through solid rock, creating a unique underwater structure. With a maximum depth of 36 feet and an average depth of 12.5 feet, Pierce Lake maintains a pool elevation of 826 feet and offers 4.2 miles of shoreline. The watershed encompasses 8,150 acres with a 50:1 ratio, allowing for a retention time of 132 days. As part of the extensive 3,092-acre Rock Cut State Park, the lake is surrounded by rolling hills, dense forests, and meandering waterways that provide a rich tapestry of natural beauty and diverse fishing opportunities.