Cedar Breaks National Monument (established in 1933) is a U.S. National Monument located in the U.S. state of Utah near Cedar City. Cedar Breaks is a natural amphitheater, stretching across 3 miles (4.8 km), with a depth of over 2,000 feet (610 m). The elevation of the rim of the amphitheater is over 10,000 feet (3,000 m) above sea level.
The amphitheater, located near the west end of the Colorado Plateau, covers the west side of the Markagunt Plateau, the same plateau that forms parts of Zion National Park. Uplift and erosion formed the canyon over millions of years, raising and then wearing away the shale, limestone, and sandstone that was deposited at the bottom of an ancient 70 by 250 miles about 60 million years ago.
The Ashdown Gorge Wilderness is within the Dixie National Forest adjacent to Cedar Breaks National Monument and characterized by extremely steep-walled canyons cut through the west rim of the Markagunt Plateau. Elevations in the wilderness range from 10,500 feet (3,200 m) to 7,500 feet (2,300 m). Rattlesnake Creek and Ashdown Creek flow through the wilderness. The 7,043 acres (28.5 km2) wilderness area was designated by the U.S. Congress in 1984 and is administered is by the United States Forest Service. Like the more famous Cedar Breaks National Monument, Ashdown Gorge is known for its multicolored rock formations and plateau-top stands of 1,000-year-old bristlecone pines.