William Henry Ashley was an American miner, land speculator, manufacturer, territorial militia general, politician, frontiersman, fur trader, entrepreneur, hunter, and slave owner. Ashley was best known for being the co-owner with Andrew Henry of the highly-successful Rocky Mountain Fur Incorporated, otherwise known as "Ashley's Hundred" for the famous mountain men working for the firm from 1822 to 1834.

A mountain man is an explorer who lives in the wilderness and makes his living from hunting and trapping. Mountain men were most common in the North American Rocky Mountains from about 1810 through to the 1880s. They were instrumental in opening up the various emigrant trails allowing Americans in the east to settle the new territories of the far west by organized wagon trains traveling over roads explored and in many cases, physically improved by the mountain men and the big fur companies, originally to serve the mule train-based inland fur trade.