Lac Vieux Desert is a lake in the United States divided between Gogebic County, Michigan, and Vilas County, Wisconsin. Fed primarily by springs in the surrounding swamps, it is the source of the Wisconsin River, which flows out of its southwest corner. The lake contains a number of small islands, especially in its northeastern lobe, including Draper Island in Michigan and Duck Island, in Wisconsin.
Lac Vieux Desert has a surface elevation 1,680 ft (510 m) above sea level, and a maximum depth of about 40 ft (12 m). The surface area is 4,260 acres (17.24 km2; 6.66 sq mi), of which approximately two-thirds is in Wisconsin and one third in Michigan.
Located in the Lake District of northern Wisconsin, the lake is a popular boating and fishing resort.