How to Research with Sanborn Maps, Fire Maps, and Survey Maps
Sanborn maps provide building-by-building detail of historical towns and cities — construction materials, number of stories, business names, and lot layouts. They are among the most underused and most powerful research tools available.
What Are Sanborn Maps?
The Sanborn Map Company produced detailed fire insurance maps for over 12,000 American towns and cities from 1867 to 2017. These maps show individual buildings, streets, lot numbers, building materials, and occupancies.
What Sanborn Maps Show:
- • Building footprints with construction materials (brick, wood, iron)
- • Number of stories and roof type
- • Business names and occupancies
- • Street names and lot numbers
- • Fire hydrant locations and water sources
- • Railroad sidings and industrial infrastructure
Where to Find Them
- • Library of Congress — Largest free collection of digitized Sanborn maps (loc.gov/collections/sanborn-maps)
- • ProQuest Digital Sanborn Maps — Complete digital collection (subscription, available through many libraries)
- • State libraries and university libraries — Many hold physical copies and microfilm
- • Local historical societies — May hold unique editions not digitized elsewhere
Other Survey Maps for Research
Master Map-Based Research
The Treasure Hunter's Research Guide includes detailed map interpretation techniques and overlay methodology.
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