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Sanborn Maps: Guide

Sanborn Fire Insurance Maps

Sanborn Fire Insurance Maps are an important research tool for the study of urban American history. The Sanborn Map Company has produced maps for underwriters and fire insurance companies since 1867. The Sanborn mapmakers attempted to show every building in the areas that they surveyed as well as each building’s means of construction, ownership and use. The maps were drawn on a scale of 50 feet to the inch and were colored to code the building material used in each structure. Maps were often produced in successive, revised editions a few years apart. More recently, many of the Sanborn maps were updated with pasted-on modifications reflecting physical changes. Comparing maps of different dates reveals patterns of urban development over time.

A good source on Sanborn maps and other fire insurance maps is:

  • Oswald, Diane L. Fire Insurance Maps: Their History and Applications. College Station, Tex.: Lacewing Press, 1997.
    HG9771 .O85 1997

Sanborn Collections

The Library of Congress owns the most complete collection of original Sanborn maps. Hunt Library holds microfilm of the Library of Congress' Sanborn maps for Pennsylvania, Massachusetts, California and Illinois. Other Sanborn originals are retained in the Sanborn Map Company Archives. Hunt Library holds microfilm versions of these maps for Pennsylvania only.

Hunt Library also has a few examples of original fire insurance maps in the University Archives. Several institutions in Pittsburgh own more extensive collections of original maps including the Archives of Industrial Society (a special collection in Hillman Library at the University of Pittsburgh), the Historical Society of Western Pennsylvania, and the Pennsylvania Room at the Carnegie Library of Pittsburgh.

How to Find Sanborn Maps in Hunt Library

Consult the following indexes to identify the maps that you want:

  • Fire Insurance Maps in the Library of Congress. Washington, D.C.: Library of Congress, 1981
    HUNT FA-REF-4 Z6026 .I7 U54 1981
  • Fire Insurance Maps from the Sanborn Map Company Archives: Late Nineteenth Century to 1990.
    HUNT FA-REF-4 HG9778 .P5 F57 1991 Guide
    HUNT MFILM-3 912.73 S19P415a Guide

Find the maps in cabinets on the third floor of Hunt Library under the following names and call numbers, and with the following date coverage:

  • Sanborn Fire Insurance Maps [Library of Congress]:
    • California HUNT MFILM-3 912.73 S19C153 ca. 1890-1955
    • Illinois HUNT MFILM-3 912.73 S19I29 ca. 1890-1976
    • Massachusetts HUNT MFILM-3 912.73 S19M414 ca. 1880-1950
    • Pennsylvania HUNT MFILM-3 912.73 S19P415 ca. 1880-1950
      These reels are labeled with the name of the state and the range of towns and entry numbers it contains.


  • Fire Insurance Maps from the Sanborn Map Company Archives: Late Nineteenth Century to 1990:
    • Pennsylvania HUNT MFILM-3 912.73 S19P415a ca. 1960-1980
      These reels are numbered to correspond with the index.


About the Maps

Each microfilmed version of a map, set of maps or volume is prefaced with information particular to it. This information can include:

  • a key to the entire mapped area with page number references
  • a key to map symbols and colors (shades of gray on microfilmed maps)
  • an index of street names and major buildings

On microfilm versions of the maps, the page numbers are alternately in the upper right and upper left corners of the frame. Other prominent numbers refer you to pages on which adjoining areas are mapped.

CAUTION: The 1950-1951 maps for Pittsburgh are updated versions of base maps from 1924-1927. The earlier dates may appear prominently on the title page, together with a subtle notation indicating the updating. Look carefully at these dates to ascertain which maps you are viewing.

See also:

  • Manufacturers Mutual Fire Insurance Company Industrial Site Maps: 1894-1954.
    HUNT MFICHE-3 338.0973 M294 SUPP. [index]
    HUNT MFICHE-3 338.0973 M294

For assistance in finding or using microforms, inquire at the Periodicals Office on the third floor of Hunt Library. For assistance in using indexes, inquire at the Arts Reference Desk on the fourth floor of Hunt Library.