70 ILCS 2605/160
As of July 6, 1955, the corporate limits of The Sanitary District of Chicago, heretofore organized under "An Act to create sanitary districts and to remove obstructions in the Des Plaines and Illinois rivers", approved May 29, 1889, as amended, are, subject to the referendum provisions of Section 2, extended so as to embrace and include within the same territory and tracts of land situated in the County of Cook and State of Illinois, not now in The Sanitary District of Chicago, described as follows:
All of the territory of Cook County, Illinois, not presently within the boundaries of The Sanitary District of Chicago, consisting of: all of the townships of Barrington, Hanover, Schaumburg, Lemont, Orland, Rich and Bloom, and all of those portions of the townships of Palatine, Wheeling, Northfield, Elk Grove, Leyden, Proviso, Lyons, Palos, Worth, Bremen and Thornton not now within said Sanitary District; except territory within any of said townships which is also within the corporate boundaries of the municipalities of Steger, Flossmoor, Olympia Fields, Matteson, Richton Park, Park Forest, South Chicago Heights, Chicago Heights, Homewood, Hazel Crest, East Hazel Crest, Thornton and Lansing.
70 ILCS 2605/160