Pacheco Pass, elevation , is a low mountain pass located in the Diablo Range in southeastern Santa Clara County, California. It is the main route through the hills separating the Santa Clara Valley and the Central Valley. As with most passes in the California Coast Ranges, it is not very high when compared to those in other mountain areas within the state. The road that traverses Pacheco Pass is State Route 152, which runs for between SR 1 in Watsonville and SR 99. Pacheco Pass Road, the western section between Gilroy and the pass itself (a distance of approximately 14 miles), is a two-lane highway from Gilroy to the junction with SR 156 and a four-lane highway over the pass; it has been the site of many accidents. Names The pass was named for Don Francisco Pérez Pacheco, noted Californio ranchero and owner of the Rancho Ausaymas y San Felipe. In the 1850s, an informal variant name for the pass was Robber's Pass attributed to the frequent hold-ups experienced by travelers using the route. History A trail nearby, through what is now Pacheco State Park, was used by the Yokuts people to cross the mountains and trade with other native people on the coast. Spanish army officer Gabriel Moraga first recorded the pass in 1805. From that time it was used by Spanish and later Mexican soldiers to cross over into the San Joaquin Valley, and for Native Americans in the 1820s and 1830s to cross westward to raid the missions and ranchos for horses and cattle. During the California Gold Rush it was used to travel between the Santa Clara Valley settlements and the goldfields and settlements in the San Joaquin Valley. However the east face of the pass was a steep and rough horse and mule trail, difficult for wheeled vehicles, until 1857 when Andrew D. Firebaugh built a wagon road with a gentler grade across the pass to what is now Bell Station, California from the Rancho San Luis Gonzaga at the foot of the Diablo Range to the east. Since then, it has been a major route between the Santa Clara Valley and the Central Valley. It was the site of Pacheco Pass Station one of the stage stations on the route of the Butterfield Overland Mail stagecoach route which connected the Saint Louis, Missouri with San Francisco from 1858 until 1861. Other stage lines used