The Grand Canyon of the Yellowstone is roughly 20 miles long, measured from the Upper Falls to the Tower Fall area. The canyon was formed by erosion as Yellowstone River flowed over progressively softer, less resistant rock.
The 109-foot (33.2-m) Upper Falls is upstream of the Lower Falls and can be seen from the Brink of the Upper Falls Trail and from Uncle Tom’s Trail. The 308-foot (93.9-m) Lower Falls can be seen from Lookout Point, Red Rock Point, Artist Point, Brink of the Lower Falls Trail, and from various points on the South Rim Trail. The volume of water flowing over the falls can vary from 63,500 gallons (240,374 l)/second at peak runoff in the spring to 5,000 gallons (18,927 l)/second in the autumn.
A third falls is located in the canyon between the Upper and Lower falls. Cascade Creek cascades into the canyon as Crystal Falls. It can be seen from the South Rim Trail just east of the Uncle Tom’s area.