Sanborn Fire Insurance Maps, Eureka, 1886-1920
Starting in 1867 the Sanborn Map Company began the production of fire insurance maps that eventually covered 12,000 communities in the United States, Canada, and Mexico. These large scale maps, drawn at scales of 1"=50' and 1"=100', were created to assist fire insurance agents in determining the degree of risk associated with commercial, industrial, and residential property within a community. Shown on the maps are the "footprints" of individual buildings, including their dimensions, shape, height, location of doors and windows, building material, and uses; and other property details and city improvements, including lot lines, street widths, fire hydrants, and other fire-fighting facilities. A key to map notations provided by the Sanborn Map Company is available.