The Sanborn Fire Insurance Maps Online Collection in the Library of Congress provides a searchable database of the fire insurance maps published by the Sanborn Map Company. Sanborn maps were created to assist fire insurance companies as they assessed the risk associated with insuring a particular property. They include information such as the outline of each building, the construction materials, street names, property boundaries, building use, and house and block numbers. Aside from maps, there may be a "key map" attached to a volume of published maps which is an index of street names.
(Detail of a Sanborn Fire Insurance Map, 1892, New Hampshire, Grafton County, Ashland)
How to read Sanborn Fire Insurance Maps
There are many methods of understanding the information found in a fire insurance map through abbreviations, color, scale, and symbols.
