The site to which the previous page points contains images of the maps included in the Chadwyck-Healey microfilm set of the Illinois Sanborn maps held by the Library of Congress, which mostly date from the years between the 1890s and 1950s. The University of Chicago Library owns part of the microform edition of this set (call number: HG9778.I3S26 1983 Microforms); photocopies from the films are clearer than printouts from the Web. The Library also owns the University Publications of America microfilm set of the collection of Illinois Sanborn maps held by the Sanborn Map Company (call number: HG9778.I3F573 1992 Microforms). These maps mostly date from the 1970s and 1980s, and so they complement the generally earlier maps in the Chadwyck-Healey/LC set. Serious researchers should consult these films as well as the maps available online. The Library also holds two volumes of paper Sanborns, covering central Chicago to the late 1950s (call number: F548.52.F25 MapRef). The paper Sanborns, unlike either the films or the maps available online, are in color and hence show building materials clearly.
For an index of the Chicago Sanborn maps, click here. The numbers show you which volume you need. This index was created by George Stachokas, University of Chicago Map Collection.