This week, Geography and Map Reading Room unveiled a new version of our website. Our reading room website is a central hub for map resources, information, and events. Explore Collections, Researcher Resources like Story Maps and databases, and read about cool maps from our collections on social media!
A few of our digital collections are highlighted on the front page, including our most-used collection, Sanborn Maps. Sanborn maps, made for fire insurance companies to assess risk, contain a wealth of detail about individual buildings. With Sanborn maps, you can learn about the development of your house, neighborhood, or town, throughout the 19th and 20th centuries.
If you’re a regular user of our Sanborn fire insurance map collection, you may have noticed our longstanding search interface redirecting to a new search interface, built into our digital collections platform. Here’s what it looks like:
From here you can search and filter the entire Sanborn collection, including both items that have been digitized and those that are only available in the Reading Room.
The Advanced Search is located in the Collection Items tab. Click on the plus sign to expand the search fields. You can also go directly to the Advanced Search, or bookmark it if you’ll want to come back to it regularly.
At the top of the Advanced Search, there’s a keyword search box. You can use that just like the usual search box at the top of the screen. Or, you can leave it blank and navigate using the menu items below.
Let’s say you’re looking for all Sanborn maps of Phoenix, New York, whether they’ve been digitized or not. While a large portion of our Sanborn collection has been digitized, we don’t scan any maps which are under copyright protection; this means that about 30% of Sanborns are only accessible in the Reading Room.
If you do a keyword search for “Phoenix,” you’ll find yourself quickly overwhelmed by Sanborn maps of Phoenix, Arizona (and Phoenixes in Oregon, Vermont, and Illinois, for that matter). So let’s limit by state:
Clicking the Search button in the bottom right pulls up a list of all 7 Sanborn maps of Phoenix, New York. For those maps that are online, you can view them right away. Volumes that aren’t available online will show a generic map symbol instead of the scanned image; if you have questions about these, feel free to contact us through Ask a Librarian.
If you’re only interested in maps that are already online, look under “Refine your results” and change “All Items” to “Available Online.”
If you’re looking for a specific year, one option is to enter the full date in the Advanced Search field (formatted one of three ways: M/D/YYYY, YYYY-MM-DD, or YYYYMMDD). Sanborn maps are only identified by month and year, so you’ll want to search by the first of the month, e.g. 4/1/1919 for April 1919.
Alternatively, you can use the Date facet on the left (or at the bottom if you’re on a mobile device) to narrow your search to a particular decade or year. The Sanborn company revisited most towns every 5 to 10 years or so to update their maps, so most towns have multiple editions.
Once you set a filter in the Advanced Search, it will change the options that you see in the following filters. For example, if I first choose New Mexico under State/Province, the County and City dropdown menus will show only counties and cities within New Mexico. If I choose Dona Ana County, the list of cities changes to just two: Hatch and Las Cruces.
At this point, you may have noticed the “Secondary Location” field. What’s that about? Let’s take a look; first, make sure to click “Clear” before starting a new search.
Starting in the 1860s, the Sanborn Map Company mapped over 12,000 cities and towns across the US. As their interest was in fire insurance, they generally limited their mapping efforts to areas of denser population, where fire insurance was more of a risk. As a result, rural areas and edges of towns are often not included in Sanborn maps. Sometimes, however, towns too small to merit their own map were included in maps of neighboring, larger towns.
These smaller areas are listed under Secondary Location. Massachusetts has a lot of these; for example, Sanborn maps of Athol, MA sometimes include Eagleville, Fryville, Pinedale, South Athol, and Roxbury. While you can filter for these using the Secondary Location menu, often the best way to find places like this is with a keyword search, especially if you don’t know which larger town it may have been included with.
In addition to maps of US cities and towns, the Sanborn collection contains a few maps of cities in Canada and Mexico, as well as some unique resources like these 1920 maps of sugar warehouses in Cuba:
We hope this search tool will make it easy to find Sanborn maps in our collections! If you have any questions about the new search interface, please don’t hesitate to reach out through Ask a Librarian, or call the Geography and Map Reading Room at (202) 707-6277.
Learn More:
- Find lots of information about Sanborn maps, including how to interpret their colors and symbols, in our research guide, Fire Insurance Maps at the Library of Congress
- We’ve made volume finders for several large cities, which can help identify which Sanborn volumes cover a specific address