These maps were created by the Sanborn Map Company to allow fire insurance companies to assess their total liability in the United States. These maps include outlines of each building; the location of windows and doors; street names; street and sidewalk widths; property boundaries; fire walls; natural features such as rivers and canals; railroad corridors; building use; house and block number; composition of building materials; strength of the local fire department; indications of sprinkler systems; locations of fire hydrants; location of water and gas mains; and names of most public buildings, churches and businesses. Sanborn maps are valuable for documenting changes in the built environment over the years.
