| | | Colusa County | CA | 06011 | | | | | nonmetro county (rural) | farm-dependent | https://maps.google.com/?q=ColusaCounty+CA |
| | | Del Norte County | CA | 06015 | | Crescent City, CA 18860 | Brookings-Crescent City,
OR-CA 152 | Central | nonmetro county (rural) | federal/state
government-dependent | https://maps.google.com/?q=DelNorteCounty+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 |
| | | Inyo County | CA | 06027 | | Bishop, CA 13860 | | Central | nonmetro county (rural) | recreation | https://maps.google.com/?q=InyoCounty+CA |
| | | Lake County | CA | 06033 | | Clearlake, CA 17340 | | Central | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=LakeCounty+CA |
| | | Lassen County | CA | 06035 | | Susanville, CA 45000 | | Central | nonmetro county (rural) | federal/state
government-dependent | https://maps.google.com/?q=LassenCounty+CA |
| | | Mariposa County | CA | 06043 | | | | | nonmetro county (rural) | recreation | https://maps.google.com/?q=MariposaCounty+CA |
| | | Mendocino County | CA | 06045 | | Ukiah, CA 46380 | | Central | nonmetro county (rural) | recreation | https://maps.google.com/?q=MendocinoCounty+CA |
| | | Modoc County | CA | 06049 | | | | | nonmetro county (rural) | federal/state
government-dependent | https://maps.google.com/?q=ModocCounty+CA |
