Humboldt County California is covered by a total of 41 ZIP Codes. There are 6 ZIP Codes in Humboldt County that extend into adjacent counties (Mendocino County, Siskiyou County, and Trinity County). Of the ZIP codes within or partially within Humboldt County there are 29 Standard ZIP Codes and 11 PO Box ZIP Codes.
Click on the ZIP Codes in the interactive map to view more information. The map control in the upper right corner can be used to toggle map layers on and off. The red outline is the border of Humboldt County and can be turned on and off. Each type of postal code can also be turned on and off.