The Schaumburg Township District Library (STDL), located in Schaumburg, Illinois, is the second largest public library in Illinois. It serves the Schaumburg Township area, covering sections of Schaumburg, Hoffman Estates, Hanover Park, Roselle, and Elk Grove Village. Both Hoffman Estates and Hanover Park have branch libraries located in the villages. Annual circulation of materials totals approximately two million items, while nearly one million people visit the library each year.

Hanover Park is a village in Cook and DuPage counties in the U.S. state of Illinois, a suburb of Chicago. The population was 37,470 at the 2020 census. Ontarioville is a neighborhood within the village.