Torch Lake is a lake in Northern Michigan. At 19 miles (31 km) long, is Michigan's longest inland lake, and at approximately 29.3 mi2 (76 km2), it is Michigan's second largest inland lake, after Houghton Lake. It has a maximum depth of 310 feet (94 m) and an average depth of 111 feet (34 m), making it Michigan's deepest inland lake, as well as the state's largest by volume.