Sauk Lake is a small, freshwater

Freshwater

Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and...

 lake located in Cook County

Cook County, Illinois

Cook County is a county in the U.S. state of Illinois, with its county seat in Chicago. It is the second most populous county in the United States after Los Angeles County. The county has 5,194,675 residents, which is 40.5 percent of all Illinois residents. Cook County's population is larger than...

, Illinois

Illinois

Illinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,...

, between the municipalities of Park Forest, Illinois and Chicago Heights, Illinois. It is an enlarged portion of Thorn Creek

Thorn Creek

Thorn Creek is a tributary of the Little Calumet River that travels through Will and Cook counties in northeastern Illinois just south of Chicago. It starts in the high land of the Valparaiso Moraine before dropping to the lower elevations of the Little Calumet River valley. Along its path it has...

 created by a dam on the south side of 26th Street, which borders the lake to the north. It is surrounded by steep, sandy bluffs on the east and west sides. It lies within the Sauk Trail Woods

Sauk Trail Woods

Sauk Trail Woods are located within the Cook County Forest Preserves in Park Forest and Chicago Heights, Illinois. They are part of the Thorn Creek Trail System. They contain miles of paved bike trails and off-trail dirt paths. Sauk Trail Woods contains Sauk Lake and Thorn Creek. The topography is...

Forest Preserve.