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Fire Insurance Maps at the Library of Congress: A Resource Guide

Sanborn FAQs

How many Sanborn sheets does the Library of Congress have?

The Library of Congress, Geography and Map Division holds approximately 675,000 Sanborn sheets in its collections. This collection is one of the largest in the world and continues to grow.

Is it possible to search the Library's online catalog for Sanborns?

Only a few Sanborn sheets are actually cataloged, though there is a collection level record. The expansiveness of the collection makes it more efficient to use a separate, searchable database to reflect holdings in the Geography and Map Division of the Library of Congress. 

Are all the Sanborn sheets available to be viewed online?

Maps that were out of copyright when the scanning project began are available on the Library's website. New images that come out of copyright, including those from 1923-1928, will be made available as soon as possible. See "Copyright Information" for further details.

How is a Sanborn map interpreted or read?

Look for the map key, often at the beginning of books, but not always. This will assist in the interpretation of the map. Fire insurance maps indicate many different building structures and codes through colors and symbols. Different building materials and resources resulted in different building styles and representations on the maps. For example, the use of adobe will not be seen in states East of the Mississippi River. Read more about this under "Interpreting Sanborn Maps" in this resource guide.

Why are copyrighted items listed if they are not available for reproduction?

The Geography and Map Sanborn Fire Insurance Maps collections spans from 1867 - 1999. The U.S. Copyright law prohibits the Geography and Map Division from reproducing items still in copyright. To assist researchers, the Geography and Map Division provides a complete listing of physical copies held by the division. Searching the database allows researchers to determine specific coverage prior to coming to the Library of Congress or contacting the nearest institution. The Sanborn Union list External provides a listing of organizations (library, archive, or historical association) with Sanborn Fire Insurance collections.