Lake Couchiching (/ˈkuːtʃətʃɪŋ/ KOO-chə-ching), from the Ojibwe gojijiing meaning "inlet", is a medium-sized lake in Central Ontario separated from Lake Simcoe by a narrow channel. The Trent-Severn Waterway enters Lake Simcoe by the Talbot River and exits this lake by the Severn River which empties into Georgian Bay. The lake is 16 km long, slightly less than 5 km wide and fairly shallow with an average depth of six metres.