Sanborn MapsThe Sanborn Map Company was a publisher of detailed maps of U.S. cities and towns in the 19th and 20th centuries. The maps were originally created to allow fire insurance companies to assess their total liability in urbanized areas of the United States. Since they contain detailed information about properties and individual buildings in approximately 12,000 U.S. cities and towns, Sanborn maps are invaluable for documenting changes in the built environment of American cities over many decades.
Sanborn held a monopoly over fire insurance maps for the majority of the 20th century, but the business declined as US insurance companies stopped using maps for underwriting in the 1960s. The last Sanborn fire maps were published on microfilm in 1977, but old Sanborn maps remain useful for historical research into urban geography. The Sanborn Map Company continues on as a geospatial solutions company. Provided by Wikipedia