Spanning the Continental Divide, from the Great Plains and across the East Slope of the Rockies, Colorado is a destination for trout anglers world-wide. It possesses an enormous wealth of trout habitat, and is home to three native cutthroat species.
Native trout populations are reasonably well documented because of Endangered Species Act reporting requirements (and funding). The Greenback population is somewhat problematic, because the documentation is older, and recent genetic testing which suggests that most restored "greenback" populations aren't greenbacks at all, but Colorado River Cutthroat which had survived long-forgotten stocking activity from the late 19th and early 20th century. CDOW is less forthcoming than many state wildlife agencies with GIS information about trout populations, though has helpfully provided information about special regulations, gold medal streams, and recommended fishing spots. The state's water quality program does designate cold water habitat. We've synthesized the available information in the webmap, and in the data available for download via the zip file.