The Sanborn Fire Insurance Map Company, established in 1867, compiled and published maps of United States cities and towns for the fire insurance industry to assess the risk of insuring a particular property. The maps are large scale plans of a city or town drawn at a scale of 50 feet to an inch, offering detailed information on the use made of commercial and industrial buildings, their size, shape and construction material. Some residential areas are also mapped. The maps show location of water mains, fire alarms and fire hydrants. They are color-coded to identify the structure (adobe, frame, brick, stone, iron) of each building.