Lake Couchiching, 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. The city of Orillia is located on the narrow channel connecting this lake with Lake Simcoe.Lakes Simcoe and Couchiching are popular spots for fishing in summer and ice fishing in winter.Singer-songwriter Gordon Lightfoot paid homage to the lake in the song Couchiching.The Couchiching Institute on Public Affairs holds its annual conference on the shores of the lake every August. Camp Couchiching is also located near the lake.Water qualityIn a 2012 study, the lake showed a microalgae density of 2.4 × 10^7/cm^2, with a high species diversity. The lake showed low total phosphorus and high organic carbon content, when compared to Lake Simcoe.