William Sherley "Old Bill" Williams (January 3, 1787 - March 1849) was a noted mountain man and frontiersman. He served as an interpreter for the government, and led several expeditions in the West. Fluent in several languages, he lived with the Osage, where he married the daughter of a chief, and with the Ute.
Williams was born on January 3, 1787 on Horse Creek, a branch of the Pacolet, under Skyuka Mountain in Polk County, North Carolina. He liked to explore and learned to trap animals for their furs, and found he had a gift for languages. Williams was the son of Joseph Williams who was invited to settle in what is now Missouri by Spanish lieutenant governor of Upper Louisiana, Zenon Trudeau in about 1795.
Williams was a master fur trapper and trail guide, becoming fluent in several Native American languages among the tribes he knew the best. He served as a sergeant and scout with the Mississippi Mounted Rangers during the War of 1812 and, as he encountered local tribes, learned their languages and customs. His ability to communicate in the different languages made him valuable to the government and the military for tribal negotiations.