County regional graticules for California.
Alameda
Alpine
Amador
Butte
Calaveras
Note: Calaveras County is almost exactly 1 degree wide - it's easternmost point is about -121.02, and westernmost point is about -121.99.
Colusa
Contra Costa
El Dorado
San Joaquin
Sacramento
Marin
Note: The bits of land within Marin County in the Bodega Bay and Farallon Islands graticules are really, really tiny. They're reachable, but the odds of a hashpoint falling in them is low.
Sonoma
Napa
Solano
Yolo
San Francisco
Good luck with the Farralon Islands graticule. The Farallon Islands are part of a National Wildlife Refuge, with access restricted to the public. The rest of the graticule is either water, or part of Marin County, or not in any county.
San Mateo
Santa Clara
Santa Cruz
San Diego
Imperial
Orange
Riverside
Los Angeles
Editor's note: San Clemente Island will probably have to be achieved by boat as the island itself is owned by the US Navy, regardless Wikipedia says it is Los Angeles County so you must succeed in this graticule to claim the LA regional achievement. Please refer to the | San Clemente Island Website for information and exclusion zones. Please read and understand | SCI Safety Zone Procedures before approaching the island.
Ventura
Santa Barbara
San Bernardino
Kern
San Luis Obispo