There is no universally agreed-upon breakdown of regions in Colorado. You'll often hear natives speak of a very simple structure comprised of the Eastern Slope (meaning everything east of the crest of the Rockies), or the Western Slope (everything west of the range crest), and anomalous Denver or the "valley". The breakdown below is a bit more complex, partly for reasons of style and partly because the simple east/west/Denver formulation lumps areas together that are really very disparate. It's also roughly what's used by the Colorado Department of Tourism. If you are confused by some of the boundaries, simply consult a map of Colorado counties, as many of the regions follow county lines. (Colorado Wikitravel)
