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Fire Insurance Map Collection

Fire insurance maps, usually referred to, by the most popular publisher, as "Sanborn maps" are incredibly useful for historical research. Chico Digital Collections now has a number of these fire insurance maps digitized for you to view online.

Fire Insurance Maps

Fire Insurance maps are rich in historical information. Originally drawn to assess fire insurance liabilities for any property within city limits, these maps are a physical representation of the changing American landscape as it developed in the industrial revolution. Today, they more frequently used in preservation and restoration efforts.


The maps are hand-drawn lithographs, usually include an index of streets and addresses, which show street names, property boundaries, the shapes of structures, identifying what materials buildings are made of, building uses, buildings proximity to fire hydrants, and the location of water and gas mains- to asses risk for fire damage.


These large scale lithograph street plans were drawn at a scale of 50 feet to one inch, and printed on 53 x 64 cm sheets of paper. These sheets are usually bound, and published as a volume. Most maps in this collection are published by the Sanborn Map company, but some are not. As the city limits grew, revisions were made to the maps, drawn on tiny slips of paper. The changes drawn by the Sanborn Map company, were then sent to local insurance companies to be pasted over the original sheets. This creates a stippling effect on the pages with many edits over the passing of time, indicating a lot of development.


This collection includes cities in Butte County and throughout Northeastern California.

Sanborn Maps

Sanborn fire insurance maps are unique because of the detailed set of symbols that convey complicated information in a clear manner. The key below outlines the detailed information that can be gathered from a Sanborn map.


The use of Red indicates a brick or tile building; Yellow indicates a frame or wood structure; Olive Green indicates a fire resistant construction; Gray indicates adobe, metal, or iron; and Blue indicates concrete and cinder block construction. The key is usually located on the first two pages of a Sanborn map, along with the street guide index, which notes which areas within the city limits are covered in the published volume set, and their corresponding sheet. 

Some of the maps in the Fire Insurance Map Collection are digitized from the microfilm copy- which means they did not retain the coloring of the original map. In these instances, it is important to use the key above as a guide for map interpretation.

Print Copies

These materials are only a few of the available copies, which have been scanned and digitized. Please, come visit us at the Meriam Library Special Collections office on the 3rd floor to take at look at our print materials. 

Meriam Library | CSU, Chico