Niles Canyon, Canyon in Alameda County, California, United States

Niles Canyon is a canyon between Sunol and Fremont cut by Alameda Creek through the eastern hills of the San Francisco Bay Area. The creek runs dark green and mostly clear over rounded grey boulders, with pale aquatic plants floating near the lower edge, and the far bank rises into a steep, vegetated slope. State Route 84, known here as Niles Canyon Road, runs the length of the canyon.

The canyon was first called Alameda Cañon, then Cañada Molina Vallejo after the two-story adobe grist mill José de Jesús Vallejo built in the early 1840s. The railroad through the canyon was completed on August 15, 1869, and the first through train from Sacramento to Alameda Terminal passed on September 6, 1869. Niles Station, named after Central Pacific attorney Addison C. Niles, gave the canyon its present name around 1900.

Essanay Film Manufacturing Company kept a studio and back lot at the canyon's western mouth from 1912 to 1916. Broncho Billy and Charlie Chaplin worked there, and Chaplin shot The Tramp in the canyon. The Niles Essanay Silent Film Museum shows exhibits, screenings and events on this heritage.

State Route 84, known as Niles Canyon Road, runs the length of the canyon from the Niles district of Fremont to Sunol. The Altamont Corridor Express trains use the Union Pacific line on the south side on weekdays and Saturdays, while the heritage Niles Canyon Railway runs the old Southern Pacific track on the north side between Sunol and Niles Station.

The two tunnels and steel bridge on the south side date from 1905–1908, when Western Pacific engineers had to bore through rock because Southern Pacific had already taken the easier north-side route. Excavators advanced about 100 feet (30 m) per month, working from both ends of the longer tunnel.