DesertUSA: John Wesley Powell - A detailed biographical overview.
John Wesley Powell - Government reports, including scanned images from Powell's reports to Congress concerning his exploration of the West.
Major John Wesley Powell - Biography of the explorer of the Colorado River, from the John Wesley Powell Memorial Museum.
The American Experience: Lost in the Grand Canyon - Companion site to the PBS series about Powell's Colorado River journey. With timeline, maps, and program information.
The Powell Expedition - A map and account of the events of the Colorado River expedition.
The Story of Major John Wesley Powell - A biography from Canyon Country Online.