Powell, John Wesley (1834–1902), a United States geologist, explorer, and ethnologist. In 1869 he led the first expedition to successfully pass through the canyons of the Colorado River. His party made the 900-mile (1,450-km) trip in large wooden rowboats. This journey and later exploration of the area formed the basis for his Explorations of The Colorado River of the West and Its Tributaries (1875), a pioneering work in structural geology. As director of the U.S. Geological Survey, 1880–94, Powell did much to advance scientific knowledge of the West through publication of detailed studies. He also served as director of the Bureau of American Ethnology of the Smithsonian Institution, 1879–1902, and his classification of the linguistic families of North American Indians was long the standard one.

Powell was born in Mount Morris, New York. He attended Wheaton (Illinois) and Oberlin colleges. During the Civil War, he rose to the rank of major in the Union Army.