Canyon Diablo, previously named "Cañon Diablo", is a canyon that winds through the Colorado Plateau approximately east of Flagstaff in northern Arizona. It is an example of an incised meander, a river bend carved into the plateau by erosion, creating a gorge. Portions of the canyon experience an ephemeral stream and act as a tributary to the Little Colorado River. Archeologists have discovered evidence of settlements belonging to the Sinagua people near the canyon dating to the 12th century. The canyon lies within both Coconino County and the Navajo Nation.
Several Old West ghost towns are located near the canyon, including the towns of Canyon Diablo and Two Guns. Three bridges span the canyon today: a railroad bridge originally associated with the Atchison, Topeka and Santa Fe Railway that connected the southern route of the first transcontinental railroad through Arizona across the canyon in 1882, but was later rebuilt and modernized in 1947; a former automobile bridge that once carried Route 66 over the canyon; and the current highway bridge that hosts Interstate 40.
Canyon Diablo is an long canyon that is located east of Flagstaff in northern Arizona. The canyon winds northeast to southwest through the high desert of the Colorado Plateau. It is composed of yellow-gray limestone that formed during the Permian, the last period of the Paleozoic. The canyon is an example of an incised meander, a river bend carved into the plateau by erosion, creating a gorge.
River incision began in the late Pliocene, approximately 2-3 million years ago or earlier, and continued, along with weathering processes occurring after incision, for several hundred thousand years. Kaibab Limestone dominates the rock formations, with an ephemeral stream within the canyon, often referred to as a wash or arroyo, acting as a tributary to the Little Colorado River. The walls of the canyon have an average height of , spanning in width and reaching a depth of near the railway bridge. At an elevation of around , its walls and channels have been compared to similar types of canyons and valleys observed on Mars.
Archaeologists have found evidence of Sinagua people settlling in areas around the canyon from 1120-1225 CE, around the time of the Elden Pueblo. In the 1850s, the Pacific Railroad Surveys were conducted in Arizona to find a route for a transcontinental railroad. Military officer Amiel Weeks Whipple participated in this survey for the U.S. Army along the 35th parallel. In mid-December 1853, Whipple found a steep canyon while riding west from a point near Winslow with a reconnaissance party, noting its name "Cañon Diablo" in his survey. The name was not officially anglicized and changed to Canyon Diablo until the early 20th century.
A cartographic map showing the new railway line crossing the canyon was published by the Atlantic and Pacific Railroad in 1881, with the railroad bridge across the gorge completed in 1882 by the Atchison, Topeka and Santa Fe Railway. A later automobile bridge, the Canyon Diablo Bridge, was constructed nearby in 1915 and once used by U.S. Route 66 to cross the canyon south of the present I-40 bridges. It is listed on the National Register of Historic Places. The railroad bridge was rebuilt in 1947 and is now known as the BNSF Canyon Diablo railroad bridge, a well-known railfan site.
The canyon passes west of Meteor Crater, and lies in the westernmost portion of the meteorite strewn field resulting from the impact that created the crater 50,000 years ago. Fragments of the meteorite have been found near the canyon. In 1891, American mineralogist Albert E. Foote was one of the first to formally study a fragment, naming it the Canyon Diablo meteorite. The convention at the time was to name a meteorite after the closest post office where the fragment was found. In 1956, American geochemist Clair Patterson notably used the meteorite to help date the age of Earth.
Portions of the canyon are located in Coconino County and Navajo Nation lands today, where it is referred to as Kin à Âigaaàin the Navajo language.