Jefferson Township, Cook County, Illinois

Jefferson Township is a former civil township in Cook County, Illinois, United States that existed as a separate municipality from 1850 until 1889 when it was annexed into the city of Chicago. During its brief history it developed from unpopulated wildlife to a largely rural community with a number of suburban villages. However, due to infrastructure limitations, legislative incentives and the lure of better municipal services it, along with numerous adjoining townships, agreed to be annexed into the city of Chicago, creating the largest city in the United States at that time.