Founded in 1867 by D. A. Sanborn, the Sanborn Map Company was the primary American publisher of fire insurance maps for nearly 100 years.
Sanborn maps were created to assist fire insurance companies as they assessed the risk associated with insuring a particular property. They include information such as the outline of each building, the size, shape and construction materials, heights, and function of structures, location of windows and doors. The maps also give street names, street and sidewalk widths, property boundaries, building use, and house and block numbers.
The Sanborn Fire Insurance Maps are a valuable resource for genealogists, historians, urban planners, teachers or anyone with a personal connection to a community, street or building. The maps depict more than 12,000 American towns and cities. They show the size, shape and construction materials of dwellings, commercial buildings, factories and other structures. They indicate both the names and width of streets, and show property boundaries and how individual buildings were used. House and block numbers are identified. They also show the location of water mains, fire alarm boxes and fire hydrants. source: News from the Library of Congress, 2017, Sanborn Fire Insurance Maps Now Online
Please visit the Library of Congress Sanborn Fire Insurance Maps website, for additional information on how to read and locate them.
Consult the legend for each map. It is usually found on the first or second page and varies from year to year.
For more information on the difference abbreviations and color coding, please consult the resources listed below.
For more information on Sanborn maps in Archives and Special Collections, check out this humorous and informative video of Professor of Anthropology Kelly Dixon, explaining how she uses Sanborn maps for archeology purposes.
Mansfield Library's Archives and Special Collections (2015). Banjo Cat: Between Two Ranges Episode 11. Retrieved from https://www.youtube.com/watch?v=cXO71Uvlweo.
Sanborn maps of Missoula and other Montana cities from 1867 to 1970 are accessible online and in the Mansfield Library.
If you have the street address and house number for where your ancestor lived, you can find out more about them by searching Sanborn maps.
1. Locate maps for that city that were published before, during, and after your ancestor(s) lived there.
2. Find the map sheet with your ancestor's neighborhood. (Use the map index on the first or second page of the volume to help you locate the correct map sheet.)
3. Find the correct address on the map sheet. This will show the property boundary lines as well as the dimensions and footprint of buildings on the lot. If the map is in color, you can discover details, such as as the building use, construction or whether it had asbestos or fire escapes. Consult the Library of Congress color key for more information.
4. Once you've located your ancestor's residence on the map sheet and studied it for details, examine the sheet for information about the neighborhood. What other kinds of buildings, homes, and businesses surrounded the home? Where there churches or schools nearby? What about factories? This will give you clues to other places you can search for records. If there is a church nearby, do they keep old records? What about a school or business where your ancestor may have attended or a business where they may have worked?
5. Then move on to comparing map sheets of the same neighborhood that were created during different years. This will help you learn more about how the neighborhood evolved. Where streets added or renamed? Was an addition built or an outbuilding converted from a stable to a garage?
These details can help you reconstruct a description of your ancestor's daily life and surroundings.