To truly understand our ancestors beyond their names and dates, we must discover how they lived. What was their neighborhood like? Where did they work? We can use census records, city directories, and newspaper articles to help with this. One other helpful genealogy resource is maps. And today, I’m specifically talking about Sanborn Fire Insurance Maps.
In this post, I’ll walk you through what Sanborn Maps are, where to find them, how to read them, and how they can add depth to your family history research.
If you’ve ever wanted to see the world your ancestor lived in, not just read about it, Sanborn Fire Insurance Maps can help. These maps are packed with details about homes, neighborhoods, and cities. And while they weren’t made for genealogy research, they’re a wonderful source of information. Let’s take a look…
What Are Sanborn Fire Insurance Maps?
David A. Sanborn was a surveyor and civil engineer who founded the Sanborn Map Company in 1867. These maps helped insurance companies assess fire risk by showing what buildings were made of, how close they were to each other, and what was nearby, like schools, factories, or lumber yards.
They mapped more than 12,000 cities and towns across the United States, continuing into the 1970s.
Each map is full of symbols and color-coded details. They don’t include people’s names, but they do show where people lived, what their homes were made of, and how their communities were laid out.
Why Sanborn Maps Matter in Genealogy
As genealogists, we often collect records that list names, dates, and places. But Sanborn Maps help us go a step further. They show us the world around our ancestors.
You might learn that your great-grandparents lived right next to a cigar factory or across from a train station. Maybe a family member ran a shop out of their home, and you can see it labeled right on the map.
These are the kinds of discoveries that make your family’s story come to life.
Where To Find Sanborn Maps Online
Many Sanborn Maps are digitized and easy to access. Here are some places to start:
- Library of Congress: This is a great free resource with thousands of Sanborn Maps. You can search by city and year. To search, go to www.loc.gov. At the top of the page, you’ll see a dropdown menu that defaults to “Everything.” Select “Maps.” Then, type “Sanborn” into the search bar. On the left side, narrow down your search by place and time.
- Online repositories: The Library of Congress website features a dedicated page for Sanborn Resources. You can find it HERE.
- Local archives or state libraries: Many state or city archives have maps in their collections. Some even include areas not found online.
How To Read a Sanborn Map
At first glance, these maps can look overwhelming. But once you learn the basics, they get easier.
- Colors: Pink usually means brick. Yellow means wood/frame. Blue or gray might mean stone or concrete.
- Numbers: These often show building dimensions in feet, including the number of stories.
- Address labels: Street names are clear, and it’s easy to see building numbers.
- Letters and symbols: There are many different letters and symbols to interpret. There’s usually a key or legend included on the first page of the map series for each town. Use it to help decode what you’re seeing on the map. If there isn’t a key or legend there, go to this resource: Interpreting Sanborn Maps.
Tip: Zoom in and move slowly. Each little detail tells a story.
What You Can Learn From Sanborn Maps
These maps don’t list people by name, but they do give us a lot of clues.
You might learn:
- The exact location of your ancestor’s home
- How close they lived to a school, church, or factory
- Whether they owned a business at their address
- If their home changed over time (additions, torn-down buildings, etc.)
- The layout of the street or neighborhood
And when you compare maps from different years, you might see how the area changed during your ancestor’s lifetime. Did their neighborhood become more industrial? Did new streets or buildings pop up around them?
These kinds of questions can lead to deeper research and new records to explore.
Example: The W.L. Blake & Company Building
Let me share a quick example. Let’s say my ancestor worked for the W.L. Blake & Company in Portland, Maine, in 1954. On the left is a photo of the building in 1954 and how it looks today.
https://digitalcommons.portlandlibrary.com/pphnegs_images_business/471
I knew the address of the building to be 79-85 Commercial Street in Portland. The map collection has 95 images, so I needed to narrow my search.
The first few images of the record set contain an index by street name. I found the building to be located on either Sheet #19 or Sheet #20.
There’s also a colorized map showing different blocks of neighborhoods:
Since I’ve seen the building in person, I know it is located on the north side of Commercial Street, so I’ll look in Sheet #19. And there it is (far right):
In this case, I did not find a key to the colors and symbols, so I used the Interpreting Sanborn Maps guide at the Library of Congress. I mentioned it previously, but you can also find it HERE.
The W.L. Blake & Co. building is a four-story brick building (pink). The street numbers are listed as 79, 83, and 85. This part of Portland is very industrial, with a machine shop located behind it, made of stone or concrete (blue), and a private truck garage nearby. There’s also a wooden storage facility (yellow). Within walking distance are a bakery and dwellings. If my ancestor lived in this neighborhood, I imagine he would have walked to work and perhaps stopped by the bakery.
The color coding made it easy to tell what materials the buildings were made of and it didn’t take up any space on the map to convey that information.
Also in these map collections is information about the population, topography, and the fire department. These were, after all, made for fire assessment risk and not genealogy!
Tips for Using Sanborn Maps With Other Records
Sanborn Maps work best when you combine them with other sources. Here are a few ideas:
- City directories: These help you match names to addresses.
- Census records: Once you know where someone lived, you can compare the street with the map.
- Deeds or land records: These can show how a property changed over time.
- Newspapers: If you find a factory fire or a store opening near your ancestor’s home, the map can show you exactly where it happened.
When you piece all these records together, the map gives everything context.
For more information about piecing together your ancestors’ lives, read my blog, “8 Ways To Research Your Ancestor’s Neighborhood.”
Limitations of Sanborn Maps
While Sanborn Maps are incredibly useful, they do have limits.
- They don’t cover rural areas, only towns and cities.
- They don’t include names of residents.
- Some maps are missing or were never made for certain towns.
- Not every year is available for every place.
Still, when a map is available, it’s worth exploring. Even if your ancestor isn’t listed by name, their world likely appears on the page.
Finally
Genealogy is more than names and dates; it’s about stories, places, and people. Sanborn Fire Insurance Maps can help you see the world your ancestors walked in. They show where they lived, what was around them, and how their communities changed over time.
So the next time you find an address in a record, look it up on a Sanborn Map. You might just discover something that brings your family history to life in a whole new way.
Genealogy tip: Even if your ancestor’s exact home isn’t shown or the address changed over time, nearby landmarks, like a church, school, or business, can help you pinpoint the right area. These landmarks often stay consistent even when street names or numbers change, making them useful reference points in your research.
Adding maps is a great way to improve your genealogy skills, but if you’re still unsure how to proceed with your research, give me a call. I’d love to help you connect with your family and tell their story. Click below to get started.
