Colorado Tax Records
From Ancestry.com Wiki
Tax records in Colorado may be found in a variety of locations. Some are located in the treasurer’s office at the county level, while others have been moved to libraries, historical societies, or the state archives. Others have been lost or, with permission of the state of Colorado, destroyed. A few dating to the 1870s or earlier have survived. The researcher may wish to check for an extant WPA Historical Records Survey (see Colorado County Resources) for the county of interest. Otherwise, a search on an individual basis will be required.