Winthrop Harbor is a village in Lake County, Illinois, United States. The population was 6,742 at the 2010 census. It is located along the northern border of Illinois and is part of the Chicago metropolitan area. Winthrop Harbor is known for its North Point Marina, and is a warning demarcation point for the National Weather Service's marine warnings for Lake Michigan. With moorage over 1,500 boats, it is the largest marina on the Great Lakes. Nearly one million visitors take advantage of the marina, its associated beaches and other recreational facilities every summer.
Winthrop Harbor was named after Winthrop, Massachusetts.
According to the 2010 census, Winthrop Harbor has a total area of 4.761 square miles (12.33 km2), of which 4.67 square miles (12.10 km2) (or 98.09%) is land and 0.091 square miles (0.24 km2) (or 1.91%) is water.
As of the 2010 United States Census, there were 6,742 people living in the village. The racial makeup of the village was 90.94% White, 1.44% Black or African American, 2.31% Asian, 0.39% Native American, 0.01% Pacific Islander, 2.03% of some other race and 2.88% of two or more races. 7.64% were Hispanic or Latino (of any race).
As of the census of 2000, there were 6,670 people, 2,370 households, and 1,884 families living in the village. The population density was 1,548.0 people per square mile (597.5/km2).