San Antonio Valley, California
The community of San Antonio Valley, also called San Antonio or San Antone, is located along the Diablo Range in eastern Santa Clara County, California. The locale is on the border of Alameda County and Stanislaus County. The sparsely populated area is located at the junction of San Antonio Valley Road, Mines Road, and Del Puerto Canyon Road. San Antonio Valley Road connects with State Route 130 (SR130) and is the shortest route to San Jose and UCO Lick. Mines Road leads to Livermore. Del Puerto Canyon Road leads to Interstate 5. The Geographic Names Information System (GNIS) shows the area as San Antonio Valley, a valley with the feature ID 232374. The ZIP Code is 94550.
Variant names 
The 1956 Thomas Brothers map spells it San Antone. This spelling mimics the way it is pronounced in common, modern usage by locals. It was spelled San Antone on the 1924 "Mount Boardman, California" U.S. Geological Survey 15-minute quadragle.
Historic variant names 
In 1776, Anza and his explorers called the area El Cañada de San Vicente.
The U.S. Postal Service established a Deforest Post Office in the area during 1892. It was moved within the area in 1897, 1906, and finally closed in 1909. Another 1924 map calls a group of buildings along San Antonio Creek, Deforest. The name comes from Ransford S. Deforest, the first Postmaster in the community.
Sphere of influence 
The area is within the sphere of influence of three different counties. The flattest and easiest drive to town is via Mines Road to Livermore in Alameda County. Del Puerto Canyon Road leads 20- to 25-miles east to the area of Interstate 5 and the Stanislaus County community of Patterson. The steepest route out, San Antonio Road, climbs west toward University of California, Lick Observatory, topping out at around 4,200 ft (1,280 m). There it turns into State Route 130 and descends into San Jose in Santa Clara County.
There is a restaurant at the junction of the three roads (Mines, San Antonio Valley, Del Puerto Canyon), appropriately called The Junction Bar and Grill. This restaurant serves as a community center as well as a stopping-off point for the many motorcycles, bicycles, and tourists that travel the roads.
The area was served by manual telephone service until deregulation forced the arrival of dial service in the early 1980s. Prior to this, a non-dial Western Electric 1A1 coin telephone served on San Antonio Road about one mile east of the Observatory. Its telephone number was San Antonio California Toll Station Number 3. Today, wired telephone numbers for the area follow the format (408) 897-xxxx. The telephone utility serving this area today is Frontier Communications.
- Santa Clara County Street Atlas, (1956 Edition), George Thomas.
- Durham, David L., Durham's Place Names of the San Francisco Bay Area, (Clovis, California: Word Dancer Press, 2000) pp. 153.
Books about the area 
Red Mountain: The Rise and Fall of a Magnesite Mining Empire, 1900-1947 by Robert W. P. Cutler, Morris Publishing, 2001, ISBN 0-9713235-0-X
I Made a Lot of Tracks by Phil Stadtler, CP Media, Bonanza, OR, 2007, ISBN 0-9759841-2-8
- CAL FIRE
- Area map (Nature Conservancy).
- This area is part of the Nature Conservancy Mount Hamilton Project.
- Unofficial photos of The Junction Café and area map