 When Cook County was incorporated in 1831, the first meeting of its government was held at Fort Dearborn with two representatives from Chicago and one from Naperville.Except for the Fort Dearborn reservation (which wouldn't become part of the city until 1839) and land reclaimed from Lake Michigan, the entirety of what is now the Loop was part of the Town of Chicago when it was initially incorporated in 1833.The area was bustling by the end of the 1830s.