The numbering plan area (NPA) includes the Sacramento Valley, including some outer suburbs of Sacramento, Shasta Cascade, and the northern Sierra Nevada.
It comprises all or sections of the following counties: Alpine, Butte, Colusa, El Dorado, Glenn, Humboldt, Lassen, Modoc, Mono, Nevada, Placer, Plumas, Shasta, Sierra, Siskiyou, Sutter, Tehama, Trinity, Yolo, and Yuba.
This area code was therefore scheduled to transition to ten-digit dialing by October 24, 2021.
[1] On June 8, 2023, the California Public Utilities Commission assigned area code 837 to overlay 530, effective January 31, 2025.
[3] Major cities in the numbering plan area include Auburn, Chico, Colfax, Davis, Grass Valley, Corning, Marysville, Oroville, Paradise, Placerville, Redding, Red Bluff, Susanville, Truckee, Woodland, Yuba City, and South Lake Tahoe.