William Henry Ashley (ca. 1778-1838), American businessman, fur trader and explorer, and politician, was a leading figure in the organization and operation of the Rocky Mountain fur trade during the 1820s.

William Ashley was born in Chesterfield County, Va. His date of birth has been given variously as 1778, 1782, and 1785; modern scholarship tends to accept the earliest date. From Virginia young Ashley migrated to Missouri. By 1805 he had settled in the St. Genevieve area, where he became a supplier for local merchants and businessmen. He married Mary Able, then turned to land speculation, operating a plantation near Cape Girardeau. By 1811 he and Andrew Henry had moved to Washington County, Mo., where Henry worked a lead mine and Ashley processed saltpeter and manufactured gunpowder.

During this time Ashley served as justice of the peace for the St. Genevieve district and as an officer in the territorial militia. During the War...