Tuesday, December 05, 2023

Historical Sanborn Maps of America

From 1866 to 1977 the Sanborn Map Company produced very accurate individual building level maps of U.S. cities and towns. The Sanborn maps provided detailed information about individual city buildings in order to enable fire insurance companies to accurately calculate fire risk. In the 1960s Fire Insurance companies stopped using maps to underwrite fire risk meaning that there was no need to create new Sanborn maps after this time. However the back-catalog of over one hundred years of detailed urban Sanborn maps still provide an invaluable resource for documenting  historical change in the built environment of American towns and cities.

Adam Cox's OldInsuranceMaps.net is a crowd-sourced project to geo-reference and digitize historical Sanborn insurance maps. It is also a great resource for anyone who is interested in exploring the history of American cities through detailed vintage maps. Using OldInsuranceMaps.net registered users can help to digitize the vast collection of vintage insurance maps owned by the Library of Congress. These digitized historical Sanborn maps of cities across the United States can then be explored by anyone on the site's map viewer.

The map viewer allows you to find and view Sanborn maps which have been geo-referenced and made into interactive maps. Select a city on the map viewer and you can view and explore that city's vintage Sanborn insurance maps using an interactive map interface. The historical Sanborn maps are overlaid on top of the modern map of the city, so it is possible to directly compare the historical maps with the modern city layout.

In some cities (for example New Orleans and Alexandria) Sanborn maps from different years are available. It is possible to use the map layer control to select the maps for different years and to use the opacity control to adjust the transparency of the selected vintage maps.


All the historical insurance maps digitized by OldInsuranceMaps.net are sourced from the Library of Congress. The Sanborn maps collection consists of over 50,000 historical atlases. Around 35,000 of them are currently available online.You can explore the LOC's digitized Sanborn maps for yourself on the Library of Congress' Sanborn Maps Collection. Using the Library of Congress Collection you can view each of the digitized Sanborn maps as an interactive online map.

You can also explore the LOC Sanborn Maps Collection using the Sanborn Maps Navigator. This map interface allows you to find and explore Sanborn maps geographically by selecting a location on a map of the United States. Select a location on the Sanborn Maps Navigator map and you can view the Sanborn atlases available for that area. The Sanborn Maps Navigator will also show you a random newspaper image from the selected area taken from the newspaper database of Chronicling America.

Once you have found and selected an individual vintage fire insurance map from the Sanborn Maps Navigator the individual map will open on the Library of Congress' website. This will allow you to explore the map in close detail using the LOC's interactive map viewer.

In the United Kingdom and Canada some fire insurance maps were created by the Charles Goad Ltd company. Unfortunately I don't think there is an extant digital interface to view the Goad maps. The British Library's Fire Insurance Maps and Plans does provide links to static Goad maps (it once used Flash to provide an interactive interface - which now no longer works). Unfortunately the British Library collection of Goad maps is difficult to search for individual maps and you can only view the maps as static images.

If you want to view the Goad maps of Scottish towns then you'll have more luck. The National Library of Scotland has geo-referenced Charles Goad Fire Insurance Plans of Scottish Towns, 1880s-1940s. This means that you can search for vintage fire insurance maps of Scottish towns and cities and view these individual maps using the library's own interactive map viewer.

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