Keppler Falls is at the upstream end of a gorge carved into Quaternary-age volcanic flows by the Firehole River. Firehole Canyon is accessible from a one-way loop road that starts just south of Madison Junction. "Kepler Cascades" was named by Col. Norris in 1881 for Kepler Hoyt, son of territorial govenor John W. Hoyt. The river drains most of the central caldera region and is relatively warm (considering the relative elevation and climate of the Yellowstone region).