Fire Insurance Maps Research Guide

What are Fire Insurance Maps?

Fire insurance maps are detailed city plans originally created to evaluate fire risk. They depict building footprints, construction materials, and property uses, along with street layouts and property lines. These maps offer a unique, granular snapshot of urban neighborhoods as they existed in the 19th and 20th centuries.

The Sanborn Map Company produced the majority of fire insurance maps, but other publisher names include Perris, Hexamer, Whipple, Baist, Bromley, or Hopkins.

A section of the 1922 Sanborn Fire Insurance map for Bellefonte, PA Sanborn Fire Insurance map for Bellefonte, PA, 1922, sheet 4.

Finding Fire Insurance Maps

Because they are a popular research resource, fire insurance maps have been scanned and made available in a variety of ways, some under commercial license provided by a library purchase or subscription. There is no single resource that has all the maps in one location.

This guide provides a suggested path for finding a Sanborn Map.

1. Start with the BTAA Geoportal Search

Begin your search with the BTAA Geoportal.
In the main search box, enter the name of your town or city.
On the results page, use the filters on the left to select “Fire insurance maps” under the Resource Type heading.

2. Browse BTAA Collections by State

If a general search doesn’t yield results, you can browse specific collections. These collections, contributed by BTAA member libraries and partners, are organized by the state they cover.

Open Access Collections

These maps are freely available to everyone.

Illinois This collection from the University of Illinois contains maps that pre-date 1923.

Indiana This collection from Indiana University contains over 10,000 maps of Indiana cities and towns, dating from the 1880s to 1925.

New Jersey This collection from Princeton University covers the state of New Jersey for the period between the 1880s and 1924.

Pennsylvania Penn State University has a near-complete collection of Sanborn maps for Pennsylvania. For items not yet in the Geoportal, the full collection can also be accessed directly at the Penn State University Libraries website.

Licensed Collections

These are commercial databases that contain high-quality, detailed scans. Access depends on your university’s subscriptions.

Find FiMO maps Full-color | 1850s-1960s | Searchable by address, coordinates, or map interface. | Sanborn and other publishers (Requires subscription)

Find ProQuest Sanborn maps Black and white | 1867-1970 | Indexed by city and state. (Requires subscription)

Comparison of Features by Fire Insurance Maps Source

Feature	Select Libraries	FiMO	ProQuest
Geographic Extent	Individual states	Varies by subscription	Varies by subscription
Color	Color	Color	Black and white
Copyright status of original materials	Public domain maps	Public domain maps	Mix of in-copyright and public domain maps
Browse and search capabilities	Search by city/town name; map search	Search by address, coordinates, or clickable map interface; city/town dropdown lists	Select city/town, then use index map (no spatial search)
Source of paper maps	Library of Congress and local acquisitions	Primarily Library of Congress (Sanborn and other atlases)	Library of Congress Sanborn Map Collection
Adding new maps?	Yes	Yes, from additional sources	No
Freely available or subscription only?	Free to all users	Subscription required (check institutional access)	Subscription required (check institutional access)

3. Explore Other Major Collections

Still can’t find what you are looking for? If you still haven’t found your map, several other institutions maintain large collections.

Library of Congress Sanborn Maps Collection The largest collection of Sanborn maps. Many are digitized and available online. Use their Sanborn Fire Insurance Maps Online Checklist to see what they hold, even if it hasn’t been scanned yet.
Union List of Sanborn & Other Fire Insurance Maps A catalog maintained by UC Berkeley that lists which libraries hold specific maps in their physical collections.
List of Online Sanborn Collections by State The University of Wisconsin-Milwaukee has compiled this helpful list of digitized collections across the country.
Microfilm Collections Many libraries hold Sanborn maps on microfilm. These are typically black and white and may be available via Interlibrary Loan. Contact your institution’s library for assistance.

How to Read Fire Insurance Maps

Each city coverage begins with a graphic index to guide the user to the correct page with each page only covering a few blocks. The original paper maps used color to indicate building materials such as yellow for wood construction and pink for brick. Some newer maps have “paste on” updates or corrections applied to a base map. Note the correction record on the index key page for dates. While Sanborn maps do not show property owner names, they can show business names. For more information, see the Library of Congress’ Introduction to the Sanborn Collection.

Key to Colors and Symbols

A color key for Sanborn maps showing building materials and features Sanborn Map key, courtesy of UC Berkeley Libraries.

Common Abbreviations

MIT Libraries’ List: A concise, two-page PDF of common abbreviations.
UC Berkeley’s Extensive List: A comprehensive list for more obscure terms.

Tutorials

This excellent tutorial from the Kansas City Public Library gives a quick history of the maps and explains how to use the indexes, keys, and colors.
How to Use Sanborn Fire Insurance Maps

BTAA Institution Guides

For more localized help or to find physical maps, consult the research guide from your specific university library.