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FAQs / Help for Sanborn Fire Insurance Maps

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. 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. Sanborn maps acquired since 1981 (the date of the original printed guide Fire Insurance Maps in the Library of Congress) are added to the database.

Are all the Sanborn sheets available to be viewed online?

Out of copyright maps (printed before January 1st, 1923) will be made available on this site, only after the complete year or volume has been scanned. New images will be made available as soon as possible. We will link the scanned image to the entry within the "URL" field of the database.

How may I obtain a copy of a Sanborn sheet?

It is possible to request a digital copy of a sheet or set of sheets that are out of copyright through the Library of Congress Photoduplication Service. A listing of prices is located on the Digital Imaging Services page and is also available by calling 202-707-5640.

If a sheet has already been scanned it is considered to be an existing file and can be purchased for a different fee than requesting a scan from original material.

Downloading JPEG2000 (JP2) files is possible by clicking on the Download JPEG200 image link below the Zoom View. The number in this link indicates the size of the compressed image. The Library maintains a list of links to software for viewing downloaded JPEG2000 files on its "How to View" page. As of July 2006, OS X supports viewing baseline JPEG2000 files natively; additional software may be needed to view large format JPEG2000 files on a MacIntosh computer. The Library of Congress cartographic JPEG2000 files are compressed at a ratio of 20:1.

How do I "Zoom" into a map?

At the bottom of each "Zoom View" and "Navigator View" window are radio buttons, used to determine the size of the "Zoom View" and the magnification.

  • First, choose a "Zoom View" size
  • Second, choose a magnification level
  • Finally, "click" on an area of the map

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 in the following essays: How to Interpret Sanborn Fire Insurance Maps, Sanborn Samplers, and Sanborn Time Series.

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

The Geography and Map Sanborn Fire Insurance Maps collections spans from 1844 - 1995. 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 as complete a listing as is possible. Searching the database allows researchers to determine specific coverage prior to coming to the Library of Congress or contacting the nearest institution. The section, Related Resources, provides a listing of the organization (library, archive, or historical association) with Sanborn Fire Insurance collections.

Scanning Sanborns

The Geography and Map Division has a long-term goal of scanning all its out-of-copyright sheets from the Sanborn Fire Insurance Map Collection. If you (or your institution) have any questions regarding the scanning of the Sanborn maps, please contact:

Edward Redmond
Reference Specialist
Geography & Map Division
Library of Congress
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  The Library of Congress >> Researchers
  February 7, 2011
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