Thornton Township is one of 29 townships in Cook County, Illinois. As of the 2010 census, its population was 169,326.
Incorporated in 1850, it is located immediately south of the city of Chicago. It is the second most populous township in Illinois as of the 2010 census, after Rockford Township in Winnebago County.
The village of South Holland serves as the governmental seat of Thornton Township. The township is named after the village of Thornton, located in the south central portion of the township. Many parts of the township carry names inspired by the village's name, including the three high schools of Thornton Township District 205: Thornton Township High School in Harvey; Thornwood High School in South Holland; Thornridge High School in Dolton; Thornton Fractional South High School in Lansing; Thornton Fractional North High School in Calumet City and Thornton Fractional Center for Academics and Technology also in Calumet City. Supervisor Frank M. Zuccarelli was voted Supervisor of the Year in 2007 by the Township Officials of Illinois for his outstanding service to the residents of Thornton Township.