Building Colorado Story by Story: The Sanborn Fire Insurance Map Collection is a digital collection of Sanborn fire insurance maps of cities across Colorado. The collection contains 346 maps of 79 principal cities in 52 counties covering the years 1883-1922.

Sanborn fire insurance maps are large scale historical city maps, detailed at the block and building level, that show residential, commercial, and industrial uses of sites, building footprints, potential environmental hazards, and construction details of structures.

Sanborn fire insurance maps were originally designed to assist fire insurance agents in determining the potential damage from fires, assessing risk, and setting premiums. Today, Sanborn maps are used for a variety of purposes, including environmental site assessment, architecture, urban history, and genealogy.

Everything you'd want to know about CU-Boulder's Sanborns:

• The print collection, the digital collection and the project
• The Accidental Map Librarian workshop