|Name origin: English|
|- location||at Sunol, California|
|- location||at Niles, California|
|- elevation||82 ft (25 m)|
|- coordinates||Coordinates: |
Niles Canyon is a canyon in the San Francisco Bay Area formed by Alameda Creek. The canyon is largely in an unincorporated area of Alameda County, while the western portion of the canyon lies within the city limits of Fremont and Union City. The stretch of State Route 84 known as Niles Canyon Road traverses the length of the canyon from the Niles district of Fremont to the unincorporated town of Sunol. Two railroads also follow the same route down the canyon from Sunol to Niles: the old Southern Pacific track along the north side, now the Niles Canyon Railway, and the newer Union Pacific (formerly the Western Pacific) track a little to the south. At the west end are the ruins of the Vallejo Flour Mill, which dates to 1856.
Essanay Film Manufacturing Company, an early motion picture company, had a studio located in Niles from 1912–1916 at the canyon's western mouth. The canyon was featured in many early films and it was here that Charlie Chaplin filmed one of his most iconic movies, The Tramp.
The route of El Camino Viejo à Los Angeles (Old Road to Los Angeles), the oldest north-south trail in the interior of Alta California, ran through Niles Canyon. In addition, the canyon was located in three different Mexican land grants - Rancho Arroyo de la Alameda, Rancho Ex-Mission San José, and Rancho Valle de San Jose.
The Union Pacific Railroad (formerly Western Pacific Railroad) has an active mainline on the south side of the canyon. The Altamont Commuter Express runs along this line on weekdays. The former Southern Pacific route from Oakland to Tracy via Niles Canyon is now abandoned, except for the portion from Sunol to Niles Station operated by the heritage railway known as the Niles Canyon Railway. This line was the original extension of the First Transcontinental Railroad from Sacramento to San Francisco Bay (by way of Stockton and the Altamont Pass) and was completed in 1869 by the Central Pacific Railroad, but lost its transcontinental traffic in 1879 to a shorter route through Benicia. The Southern Pacific tracks in Niles Canyon are on the north side of the canyon. Southern Pacific, being the first railroad in the canyon, chose the best route. Therefore, when the Western Pacific tracks were laid through the canyon in 1908, they were left with a more difficult challenge. This forced Western Pacific engineers to bore two tunnels and construct a steel bridge to lay their tracks. When driving the longer of the two tunnels, two gangs of excavators worked on it, one driving the tunnel from the east end and the other from the west end. The excavators drove about 100 feet per month.
- U.S. Geological Survey Geographic Names Information System: Niles Canyon
- Earle E. Williams, Tales of Old San Joaquin City, San Joaquin Historian, Published Quarterly, By San Joaquin County Historical Society, VOL. IX, No. 2, APRIL - JUNE 1973. p.13, note 8. "El Camino Viejo ran along the eastern edge of the Coast Range hills in the San Joaquin Valley northward to the mouth of Corral Hollow. From this point it ran generally east-west through the hills and then down into the Livermore Valley and on to Mission San Jose. From there it turned northward, terminating at what is now the Oakland area. ... see Earle E. Williarms, Old Spanish Trails of Ihe San Joaquin Valley, (Tracy, California), 1965."
- Nale, Bill. "Livermore History - Railroads 1". eLivermore.com. Livermore, California. Retrieved 2016-03-12.
- Bender, Henry E. Jr. "Southern Pacific Sunol Depot Returns". Retrieved 2016-03-14.
Southern Pacific’s line from Niles through Niles Canyon, Livermore, and Altamont Pass to Tracy was completed by the first Western Pacific Railroad (which was a Central Pacific subsidiary by then) in September 1869. It was the first railroad connecting the San Francisco Bay Area to Sacramento and the Transcontinental RailroadFrom The Ferroequinologist.
- Rattenne, Ken. "The 'Other' Canyon". Retrieved 2016-03-14. Excerpted from Rattenne, Ken (February 1990). The Feather River Route, Volume I. Interurban Press. ISBN 978-0870460913.
- " "Tunnel Soon to Be Completed". Brotherhood of Locomotive Firemen and Enginemen's Magazine (Indianapolis: Brotherhood of Locomotive Firemen and Enginemen). Vol. 44 (No. 3): p. 333. March 1908.
If the present progress of driving the Niles Canyon tunnel of the Western Pacific Railroad is continued, it is believed that trains will be running through the mountains by the first of July, 1908.