Dauphin Lake is located in western Manitoba near the city of Dauphin, Manitoba. The lake covers an area of 201 square miles (520 km²) and has a drainage basin of about 3,420 square miles (8,900 km²). The Mossy River drains the lake into Lake Winnipegosis. The basin is drained by seven major streams and has a total relief of 1,900 feet (580 m).