Sanborn Fire Insurance maps of towns and cities throughout the United States were produced for insurance underwriters who needed to know the details of a building and its surroundings in order to assess risks and set rates. Most of these date to after 1884 when the Library of Congress established new copyright requirements. The maps show a wealth of information about buildings including materials, number of stories, locations of doors and windows, and the presence of basements.  They also often include notations as to use (such as store, stable, Post Office, church, saloon, theatre, and residence/dwelling) or the ethnicity or occupations of the occupants.  Information is also included on locations of sidewalks, water pipes, fire hydrants, cisterns, wells, and privies.  There is a Key on each map folio describing the symbols used. Sanborn Maps are an invaluable resource for historians and genealogists as well as anyone interested in the history of their community.