| | Amador County | CA | 06005 | | | | | nonmetro county (rural) | federal/state
government-dependent | https://maps.google.com/?q=AmadorCounty+CA |
| | Butte County | CA | 06007 | | Chico, CA 17020 | | Central | metro county (urban) | nonspecialized | https://maps.google.com/?q=ButteCounty+CA |
| | Calaveras County | CA | 06009 | | | | | nonmetro county (rural) | recreation | https://maps.google.com/?q=CalaverasCounty+CA |
| | Colusa County | CA | 06011 | | | | | nonmetro county (rural) | farm-dependent | https://maps.google.com/?q=ColusaCounty+CA |
| | Glenn County | CA | 06021 | | | | | nonmetro county (rural) | farm-dependent | https://maps.google.com/?q=GlennCounty+CA |
| | Humboldt County | CA | 06023 | | Eureka-Arcata, CA 21700 | | Central | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=HumboldtCounty+CA |
| | Imperial County | CA | 06025 | | El Centro, CA 20940 | | Central | metro county (urban) | federal/state
government-dependent | https://maps.google.com/?q=ImperialCounty+CA |
| | Inyo County | CA | 06027 | | Bishop, CA 13860 | | Central | nonmetro county (rural) | recreation | https://maps.google.com/?q=InyoCounty+CA |
| | Kern County | CA | 06029 | | Bakersfield-Delano, CA 12540 | | Central | metro county (urban) | nonspecialized | https://maps.google.com/?q=KernCounty+CA |
| | Lake County | CA | 06033 | | Clearlake, CA 17340 | | Central | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=LakeCounty+CA |