Cañon City () is a Home Rule Municipality that is the county seat and the most populous municipality of Fremont County, Colorado, United States. The city population was 16,400 at the 2010 United States Census. Cañon City straddles the easterly flowing Arkansas River and is a popular tourist destination for sightseeing, whitewater rafting, and rock climbing. The city is known for its many public parks, fossil discoveries, Skyline Drive, The Royal Gorge railroad, the Royal Gorge, and extensive natural hiking paths.
In 1994, the United States Board on Geographic Names approved adding the tilde to the official name of Cañon City, a change from Canon City as the official name in its decisions of 1906 and 1975. It is one of the few U.S. cities to have the Spanish Ñ in its name, others being La Cañada Flintridge, California; Española, New Mexico; Peñasco, New Mexico; and Cañones, New Mexico.
Cañon City was laid out on January 17, 1858, during the Pike's Peak Gold Rush, but then the land was left idle. A new company "jumped the claim" to the town's site in late 1859, and it put up the first building in February 1860. This town was originally intended as a commercial center for mining in South Park and the upper Arkansas River.
In 1861, the town raised two companies of volunteers to serve with the Second Colorado Infantry during the American Civil War. This regiment fought in skirmishes in nearby New Mexico and as far east as the Indian Territory (Oklahoma) and Missouri before ending its organization in 1865.
In 1862, A. M. Cassaday drilled for petroleum 6 miles (10 km) north of Cañon City, close to a known oil seep.