GHL Blog Rotating Header Image

Tip of the week: Using Sanborn Maps

Share Button

Sanborn maps are a valuable research tool. These maps are fire insurance maps dating 1866-1959. Approximately 3,000 cities have Sanborn maps that cover all 50 U.S. states, Canada, and Mexico.

North Carolina maps include 145 towns within 85 counties; however, different cities have maps for different years. For example, the town of Hertford in Perquimans County has maps for the years of 1916, 1923, 1929-1940. On the other hand, Concord in Cabarrus County has maps dated 1885, 1887, 1892, 1897, 1902, 1906, 1911, 1921, and 1927.

Understanding Sanborn Maps

Sanborn maps are highly visual. They contain a lot of information using colors and codes. The Library of Congress has a key to the colors and codes you will see on the maps.


Sanborn maps use color to convey information about buildings that would otherwise be unknown. For example, blue identifies stone or concrete-made buildings. Pink represents buildings made of brick or tile. Yellow represents frame buildings. Some buildings may be constructed from multiple types of material, such as a frame house with a brick front. Colors can be combined in various ways to illustrate this.


Codes can tell you several things. See the key for the full list. Below is a list of some common codes:

  • How tall and how many stories a building has
  • Dimensions of a building
  • If the building is constructed with non-flammable material
  • Any special hazards in the building
  • The type of building, such as dwelling, store, and factory

In addition to the codes used for all maps, many have an index on the first page, which list numbers representing different buildings, sometimes with the names of businesses and then corresponding numbers on the map to identify the location of those buildings..

How to Access

There are multiple ways to access Sanborn maps. Repositories, such as the State Archives of North Carolina, have limited maps you can view in person. There are also online resources to view maps.

The Library of Congress website has the most maps available online and free to view. To date, the Library of Congress has nearly 25,000 images of maps already online. In May 2017, they announced an initiative to digitize  more. Maps will be added monthly until 2020, for a total of approximately 500,000.

Sanborn maps by 2020 for over 500,000 images when the project is complete. The maps online are updated monthly.

Heritage Quest, which can be accessed through NCLIVE, has Sanborn maps for North Carolina, but the color has been removed. If you are primarily interested in location, such as street names, Heritage Quest maps work well for that purpose. If you want to see all the details, Library of Congress maps will serve your needs better.

Did you know? If you are a North Carolina resident with a library card from any public library within the state, you can access Heritage Quest from your home using NCLIVE. This service is only available for North Carolina residents. You can also access Sanborn maps directly through NCLIVE.

Sanborn maps can provide great information for researchers. Not only can they show where an ancestor lived, the can show information on the building and the town and changes throughout time. These are great tools for research and should not be overlooked.

One Comment

  1. Jim Laughrun says:

    Another source that you might want to mention is the website, “North Carolina Maps.” I have used the Sanborn maps extensively from that collection and find them easy to navigate.

Leave a Reply

Your email address will not be published. Required fields are marked *

This blog is a service of the State Library of North Carolina, part of the NC Department of Natural and Cultural Resources. Blog comments and posts may be subject to Public Records Law and may be disclosed to third parties.