Colorado. Round up on the Cimarron original

Colorado. "Round up" on the Cimarron, a photochrom print from c. 1898, showing one of the large musters of cattle done in the days before barbed wire, fences, and easy access to transport ended the necessity for the practice.

The Library of Congress identifies this as being on the Cimarron River, which would put this in the extreme southeast of Colorado; I don't know, however, if the necessary mountain is there or not.