This collection includes real estate and fire insurance atlases for many Colorado, Wyoming and New Mexico towns. Most of these have been updated with paste-over additions. The maps show footprints of structures and will help you to date the construction of a building and give you a picture of neighborhood development. They also show the legal description (addition name, lot, and block numbers) of your building, which is necessary for locating many historic building records. An online collection of Colorado, Wyoming and New Mexico Sanborn Atlases without paste-over updates is available in the Library or from home with a DPL Library card. For more information see the Denver Building History Tutorial.