List of county seats of California:

Alameda County: Oakland
Alpine County: Markleeville
Amador County: Jackson
Butte County: Oroville
Calaveras County: San Andreas
Colusa County: Colusa
Contra Costa County: Martinez
Del Norte County: Crescent City
El Dorado County: Placerville
Fresno County: Fresno
Glenn County: Willows
Humboldt County: Eureka
Imperial County: El Centro
Inyo County: Independence
Kern County: Bakersfield
Kings County: Hanford
Lake County: Lakeport
Lassen County: Susanville
Los Angeles County: Los Angeles
Madera County: Madera
Marin County: San Rafael
Mariposa County : Mariposa
Mendocino County: Ukiah
Merced County: Merced
Modoc County: Alturas
Mono County: Bridgeport
Monterey County: Salinas
Napa County: Napa
Nevada County: Nevada City
Orange County: Santa Ana
Placer County: Auburn
Plumas County: Quincy
Riverside County: Riverside
Sacramento County: Sacramento
San Benito County: Hollister
San Bernardino County: San Bernardino
San Diego County: San Diego
San Francisco County: San Francisco
San Joaquin County: Stockton
San Luis Obispo County: San Luis Obispo
San Mateo County: Redwood City
Santa Barbara County: Santa Barbara
Santa Clara County: San Jose
Santa Cruz County: Santa Cruz
Shasta County: Redding
Sierra County: Downieville
Siskiyou County: Yreka
Solano County: Fairfield
Sonoma County: Santa Rosa
Stanislaus County: Modesto
Sutter County: Yuba City
Tehama County: Red Bluff
Trinity County: Weaverville
Tulare County: Visalia
Tuolumne County: Sonora
Ventura County: Ventura
Yolo County: Woodland
Yuba County: Marysville

This obviously works best in large counties, and in counties with a very large aspect ratio (length to width). For example, if you look at a map of counties and county seats in California, you'll notice that in the Sierra Nevada region, most counties extend far up into the mountains, with their county seats in the lowlands (far western sides). So if you're from the big urban areas and you're ticketed in the high sierra, you can move the trial an hour or more away from where you got the ticket. The best places to use this are probably the Sierra counties, and the very large Southern California counties with their county seats all the way at one corner of the county: Riverside and San Bernardino. So if you're from urban California and ticketed while driving to Vegas on I-15, demand to be tried in San Bernardino.

I guess another thing to take away from this is that if you're going to speed, especially if you have no CMs, do it farther from the county seat than where you live/work. At least if you get unlucky and get a ticket, you have a better chance of getting it dismissed.