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University of Colorado
1157 18th St. (18th and Colorado), Box 184
Boulder, CO 80309-0184
Their Government Publications Department is a federal regional depository as well as a Colorado state publications depository. It holds nearly complete microfilmed census population schedules and Soundexes, in addition to many other publications of interest to Colorado and other researchers. The Archives Department has many printed and manuscript materials relating to Colorado and Western history.