All fire insurance maps share a single purpose – to provide risk assessment for real property before issuing fire insurance on that property – and this purpose is reflected in the often unique information shown on them. This includes information like where fire hydrants are, what type of material a building is made from, and even the width of nearby water lines. For maps showing property ownership and for plat maps, see our research guide on Real Estate Maps. Fire insurance maps are excellent for tracking urban growth and building history. For economic reasons, rural areas were not mapped except for large mining operations and related facilities. If you're tracking the development of a neighborhood or want to see building footprints over time, we recommend you explore both real estate maps as well as fire insurance maps, since both types of maps will show this and at different points in time. The overlap in content between the two types, even though varied and limited, makes them useful for looking at an individual property over time.
Most fire insurance maps made in the Rocky Mountain region were created and sold by Sanborn Map Company, founded in New York in 1866. Sanborn issued its first maps for a few towns in Colorado in 1883, and continued to produce maps for Colorado until the 1970s. Additional coverage and updates created by individual insurance agents, especially the Mountain States Inspection Bureau, are also available. For a full list of known fire insurance maps for Colorado, with a detailed background and guide, consult the Fire Insurance Map Inventory of Colorado. That inventory includes information about the various editions and formats available for each town, including editions held by other institutions.
The Special Collections and Archives fire insurance map collection includes:
- Colorado: Full-color print editions for numerous towns, cities, and mining operations. Microfilm and online access (ProQuest) to black-and-white Sanborn maps from 1883-1951. Denver color Sanborn maps from the 1887 edition in our digital collections.
- Wyoming: Full-color print editions for selected towns and cities. Microfilm and online access (ProQuest) to black-and-white Sanborn maps from 1883-1960.
- New Mexico: Full-color print editions for a small number of locations. Online access (ProQuest) to black-and-white Sanborn maps from 1883-1957.
DENVER SANBORN MAPS
Sanborn maps for Denver required multiple volumes, and to help locate the right volume the Library of Congress developed its Sanborn Atlas Volume Finder, which includes Denver. Digitized versions from the Library of Congress and the University of Colorado at Boulder come from two different copies of the same atlas, and therefore should be identical in content. The ProQuest online database maps were derived from the microfilm edition, which in turn was produced from the Library of Congress original maps. ProQuest currently provides the only digital representation available for the 1930 edition and its 1951 update.
Available print atlases at Denver Public Library include:
- 1887 edition
- 1890/93 edition (updated to 1897)
- 1903/04 edition (updated to 1929)
- 1929/30 edition (updated to 1937)
- 1929/30 edition (updated to 1956)
- 1929/30 edition (updated to 1958)
- 1929/30 edition (updated to 1962)
- 1961 edition (updated to 1969)
- 1969 edition (reduced format, updated to 1974)
In the Dig Deeper section you can find links to online Sanborn maps. Note that the ProQuest database requires a current Denver Public Library card to access unless you're in one of our branch locations. Using fire insurance maps can be a complicated process with no single prescribed path. Do not hesitate to ask one of our special collections librarians if you need assistance.
Fire Insurance Map Inventory of Colorado
Detailed inventory of known Colorado fire insurance maps held by Colorado institutions and the Library of Congress. Includes introduction and guide to the history of fire insurance mapping in Colorado, how to use the inventory, and where you can find fire insurance maps in the state.