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Highlights Archives

Sanborn Fire Insurance Maps Going Online


An 1883 Sanborn Fire Map of Appleton

Archivists have finished scanning and publishing online about half of the Society's 8,000 Sanborn Fire Insurance maps. Because they show every building on every block in meticulous detail, Sanborns are highly sought after by genealogists, city planners, archaeologists, local historians and environmentalists. Once an obscure and esoteric resource, today they are one of the Society's most popular collections. They are being made available for free thanks to the generous financial support of the Caxambas Foundation of Milwaukee.

Old Maps Put to New Uses

Sanborn maps were published between the 1870s and 1950s so local insurance agents could assess the risk of fire breaking out on a client's premises. They outline each building, including the type of heating, size and number of stories, the location of windows and doors, and similar structural features. Through color coding, they even show the composition of building materials. They also document the strength of the local fire department and the presence of hazards such as blacksmith forges, bakeries or stored kerosene, and the existence of firefighting equipment, cisterns or community water works. They also note streets, rivers, canals, railroad corridors and other topographic features. Most Sanborn maps focus on downtowns, but some include large portions of residential areas. Individual homes are recorded with the same precision as large factories.

Because they were updated every few years, Sanborn maps recorded changes to neighborhoods and buildings in fascinating detail. This enables modern investigators to learn when changes were made to historic buildings. It allows environmentalists to see precisely what industrial processes occured at a given spot. It often lets genealogists examine their ancestors' homes or workplaces and compare them to those of their neighbors.

Comprehensive Coverage

By the spring of 2014 researchers will be able to examine 8,000 sheets of Sanborn maps showing more than 300 cities and towns between 1870 and 1923. Archivist Laura Farley oversees a team of five University of Wisconsin graduate students who are scanning, editing, indexing and publishing the maps. They work alphabetically, and have completed Ableman through Marinette. The 800 maps of Milwaukee, as well as some from other large cities, present special handling challenges and will be scanned after the rest of the state is finished next spring. Original paper copies of Sanborn maps for all communities can be seen in the Archives Research Room (608-264-6460) while the project is underway.

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:: Posted November 7, 2013

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