John Wesley Powell was born 24 March 1834 at Mount Morris in western New York state. His parents moved to Illinois, where he was educated at Wheaton and Oberlin colleges. He became interested in botany and geology at an early age, and began geological work with a series of field trips, including a trip the length of the Mississippi River in a rowboat; he also traveled the Ohio and Illinois rivers.
In 1861 he enlisted in the Union Army and was commissioned a captain when he recruited a company of artillery. At the battle of Shiloh he lost his right arm at the elbow. He nevertheless returned to active duty and was promoted to the rank of major.
After his discharge in 1865, he was appointed professor of geology and curator of the museum at Illinois Wesleyan University at Bloomington. He later became a lecturer and curator at the museum of Illinois Normal University.