Athearn, Frederic J. An Isolated Empire: A History of Northwest Colorado. Denver: Colorado State Office, Bureau of Land Management, 1976.
This useful government publication contains the following chapters:
- Northwestern Colorado Prior to Exploration
- The Fur Trade
- Exploration in Northwestern Colorado
- Mining and Transportation in Early Western Colorado
- Confrontations: Settlement Versus the Ute Indians
- Settlement in Middle Park and the Yampa Valley
- Development of the Cattle and Sheep Industry
- Mining and Transportation 1890-1920
- The "Moffat Road" and Northwestern Colorado, 1903-1948
- Development of Northwestern Colorado 1890-1940
It can be found online in the HathiTrust Digital Library or in many Federal Depository Library Program libraries.