Mashapaug Lake is a 297-acre (1.20 km2) lake surrounded by Bigelow Hollow State Park and Nipmuck State Forest in the town of Union in northeastern Connecticut. The lake has a maximum depth of 39.5 feet (12.0 meters), and an average depth of 15 feet (4.6 meters). Its normal surface elevation is 706 feet. The lake is very popular with fishermen and boaters from the area, and can also be used for swimming.