Willow Lake, Illinois

Willow Lake is a census-designated place (CDP) surrounding a lake of the same name in Stephenson County, Illinois, United States. It is in the center of the county, on the north side of U.S. Route 20 and 3 mi north of the center of Freeport, the county seat.

Willow Lake was first listed as a CDP prior to the 2020 census.