The San Gorgonio Pass, or Banning Pass, is a 2,600 ft (790 m) elevation gap on the rim of the Great Basin between the San Bernardino Mountains to the north and the San Jacinto Mountains to the south. The pass was formed by the San Andreas Fault, a major transform fault between the Pacific plate and the North American plate that is slipping at a rate of 7.2 ±2.8 mm/year. The tall mountain ranges on either side of the pass result in the pass being a transitional zone from a Mediterranean climate west of the pass, to a Desert climate east of the pass. This also makes the pass area one of the windiest places in the United States, and why it is home to the San Gorgonio Pass wind farm.
It serves as a major transportation corridor between the Greater Los Angeles region and the Coachella Valley, and ultimately into Arizona and the United States interior. Both Interstate 10, and the Union Pacific Railroad, utilize the pass. When the rail line was completed in January 1883, by the Southern Pacific Railroad, it was billed as the second U.S. transcontinental railroad.
