Lake Billy Chinook is a reservoir in Jefferson County in the U.S. state of Oregon. Created by the Round Butte Dam in 1964, Lake Billy Chinook lies in a canyon at the confluence of the Crooked, Deschutes, and Metolius rivers near Culver and Madras. It was named for Billy Chinook, a Native American of the Wasco tribe who traveled alongside American explorers John C. Frémont and Kit Carson in their expeditions of 1843 and 1844.