Historic Port of Washington Project: https://hpow.org
Washington Harbor District, Then and Now: https://hpow.org/thenandnow/
Sanborn maps contain detailed information about properties and individual buildings in approximately 12,000 U.S. cities and towns and were originally created to allow fire insurance companies to assess their total liability in urbanized areas of the United States. Sanborn maps are invaluable for documenting changes in the built environment of American cities over many decades.
The maps include outlines of each building and outbuilding; the location of windows and doors; street names; street and sidewalk widths; property boundaries; fire walls; natural features (rivers, canals, etc.); railroad corridors; building use (sometimes even particular room uses); house and block number; as well as the composition of building materials including the framing, flooring, and roofing materials; the strength of the local fire department; indications of sprinkler systems; locations of fire hydrants; location of water and gas mains; and even the names of most public buildings, churches and businesses.
Unique information includes the location of the homes of prominent individuals, brothels, and more ephemeral buildings including outhouses and stables.
To see a sample map from Washington, NC, click here.