The Grand Canyon of the Yellowstone is the most breathtaking sight inside Yellowstone National Park. Twenty miles long, the canyon is up to 4,000-feet wide and 1,200-feet deep in places. It's located on the eastern side of the park. From several vantage points, you can view Lower Falls plunging steeply into the canyon 308 feet, or the Upper Falls tumbling 109 feet.
Charles Cook explored the area in 1869, and is credited with discovering the canyon. According to Yellowstone historian Lee Whittlesey’s book Yellowstone Place Names, Cook was said to have commented: “I sat there in amazement, while my companions came up, and after that, it seemed to me that it was five minutes before anyone spoke.”
The canyon is in a former geyser basin created by rhyolite lava flows, heat and faulting. Chemical and heat action resulted in hydrothermal changes that today can be seen in the form of active geysers and hot springs. It is believed that at the end of the last glacial period melting ice dams at the mouth of Yellowstone Lake caused catastrophic flooding and erosion that led to the formation of the canyon as it exists today.
What Created the Grand Canyon of the Yellowstone Pink and Yellow Colors?
Mineral stains mark the locations of hot springs and steam vents in the canyon walls. For thousands of years, upwardly percolating fluids have altered the chemistry of the rocks, turning them yellow, red, white, and pink.
When the old geyser basin was active, the "cooking" of the rock caused chemical alterations in the canyon's iron compounds. The rocks are essentially rusting. The colors indicate the presence or absence of water in the individual iron compounds. Most of the yellows in the canyon are the result of iron present in the rock rather than sulfur, as many people think.
The 19th century painter Thomas Moran said, "its beautiful tints were beyond the reach of human art."
Grand Canyon of the Yellowstone Trail Updates
People visiting the Grand Canyon of the Yellowstone River are now able to enjoy the view from the newly renovated Inspiration Point reopened in 2018. The next construction projects include the South Rim Trail, Uncle Tom’s Point and the Brink of Upper Falls. Watch for progress updates at www.nps.gov/yell/planyourvisit/canyonprojects.htm.