Although I’ve been a genealogist for many years, I’m constantly trying to improve my skills. Recently I attended a program on using Sanborn Fire Insurance Maps that brought to the forefront this genealogical goldmine of a resource I’ve almost forgotten about in my own research.
The Sanborn Fire Insurance Maps were originally created in 1867. These large-scale diagrams were designed to help insurance agents assess fire risks by detailing the layout and construction of buildings in more than 12,000 U.S. towns and cities. Today, they serve as an amazing tool for genealogists to move beyond names and dates into the more physical world of their ancestors.
The primary use of Sanborn maps in genealogy is to pinpoint the exact location and physical structure of an ancestor’s residence. While census records or city directories might provide a street address, Sanborn maps bring that address to life with:
• building details – These maps indicate whether a house was brick (usually colored pink/red) or wood frame (yellow), the type of roof, and the number of stories.
• property layout – You can see outbuildings on the property such as stables, sheds or garages, as well as other homes/neighbors and fire hazards such as factories or lumber yards.
• address verification – Since street names and house numbers often changed over time, comparing maps from different years allows us to track an ancestor even when the address shifted.
Also, by seeing the neighborhood, genealogists can learn so much about an ancestor’s everyday life. Grocery stores, banks, churches, schools and workplaces help estimate how far they would need to travel for work, school or errands. Industrial sites in their neighborhood may also reflect their economic status.
Because the Sanborn Map Company updated their maps periodically — sometimes every few years — genealogists can use them to create a “time-lapse” view of an ancestor’s life. For example, you might see a small house on an 1890 map replaced by a larger structure or an added porch in a 1910 edition. Maps also show the transition of a neighborhood from residential to commercial.
For myself, I located my maternal grandparents’ address in Canada. The details on the census weren’t clear, but I knew that several family members were living at this same address and in my mind, they are all sharing a small home like my paternal grandparents when they first arrived from Italy. But in reviewing the Sanborn Map I found they were living in a multi-family building (apartments) which put to bed my image of 22 people in a small home. I had also found their employer — they all worked for the same company — was a block away from their home, as was the children’s school.
If you’re ready to jump into Sanborn Maps, the Library of Congress (https://www.loc.gov/collections/sanborn-maps) is the most comprehensive source, with nearly 25,000 maps currently available online for free. You can find more information on a specific Sanborn map by first visiting https://www.loc.gov/collections/sanborn-maps/about-this-collection/. Here you will find help deciphering color codes and symbols, info on how to interpret indexes, scale, abbreviations, line style and sheet numbers along with publication dates.
By using Sanborn maps with traditional records like the census or deeds, you will see your ancestor’s everyday life so much more clearly.