The Grand Canyon of the Yellowstone is a dramatic feature that can’t be missed on any visit to Yellowstone National Park. This 24-mile-long canyon averages around 1,000 feet deep and a half mile wide, making it an excellent vista to view Yellowstone Lower Falls and the Yellowstone River. The rock of the canyon is also what gave the region it’s name.
There are several vistas to see along the canyon, with Artist Point on the south rim getting better light in the early morning, and the two vistas on the northern rim, Lookout Point and Grand View, being more popular in the afternoon. There are a variety of short trails along the edge of the canyon that give access to additional views such as Lower Lookout Point, where visitors will find a great close-up of Lower Falls.
Contrary to what most people think, the yellows in the canyon wall are not the result of sulfur in the rock. The yellow is the result of hydrothermal alteration to iron in the rock. The thermal activity of the previously active geyser basin cooked the rock, causing chemical alterations in the iron compounds, the oxidation of which causes the discoloration.