Illinois County Boundaries: 1790 to Present – by Michael L. Hébert
1875 Township Map – USGenWeb Project – Illinois Digital Map Library
Modern Township Map – Illinois Secretary of State’s website
Cities and Towns
Sanborn Fire Insurance Maps – This map collection is only available to the Consortium of Academic and Research Libraries in Illinois (CARLI) member libraries. Here is a list of libraries. A login is required.
1940 Aerial Photographs – 1937-1947 Illinois Historical Aerial Photography
1954/55 Farmsteads – American Aerial County History Series – by John Drury