Sanborn Fire Insurance Maps:
Sanborn maps are extremely detailed maps of many large U.S. cities and towns produced from the mid-1800’s thru 1977.
Originally published by The Sanborn Map Company, their purpose was to provide fire insurance companies with information on building structures in order to assess liability in the event of fire. The volumes contain an index of streets and addresses, and a special index for businesses, churches, schools and other notable establishments.
The maps themselves include a variety of information: outlines of each building and “outbuilding;” location of windows and doors; street names and street widths; property boundaries; house and block numbers; rivers, creeks and other natural features; building use; as well as what building materials were used on the structure.