Home Regional Boundaries
The five regions mentioned in Article IX, Section 1 of the State By‐Laws, are bound as follows:
- Northern – includes Sonoma, Napa, Solano, Sacramento, Amador, Calaveras, Alpine, and Mono counties, as well as all counties north of these.
- Central – includes all counties between the Coast Range ridge line on the west and the Sierra Nevada ridge line on the east, from San Joaquin, Stanislaus, and Tuolumne counties at the north end to Kern County at the south (note that portion of Kern County east of the Sierra Nevada ridge line is excluded from the Central Region).
- Central Coast: all counties west of the Coast Range ridge line, from Marin and Contra Costa counties in the north to San Luis Obispo County in the south.
- South Central – includes Inyo, Kern (east of Sierra Nevada crest only), Ventura and Santa Barbara counties, and all of Los Angeles County except for the small, south-easterly portion designated below as part of the Southern Region.
- Southern – includes San Bernardino and Orange Counties, as well as all counties south of these, and a small portion of Los Angeles County bordered as follows: on the west, by the San Gabriel River, running north from the I-405 freeway bridge until it reaches Azusa city limit at Huntington Dr/Foothill Blvd, on the west by the Azusa city limit running north to its intersection with the Angeles National Forest boundary, then on the north by the Angeles National Forest boundary, running east to the San Bernardino County line.