Humboldt County, California has 38 ZIP codes in this list, from 95501 to 95589. They cover 35 places, among them Eureka, Arcata, Alderpoint and Blocksburg.
The ZIP code areas of Humboldt County add up to about 2,657 square miles of land (6,882 sq km) as the Census Bureau draws them. The largest is 95542 (Garberville), with 220 square miles.
Places with more than one code here: Eureka (3 codes), Arcata (2 codes).
Using these codes
In an address, the ZIP code comes last, after the city and the two-letter state: Eureka, CA 95501.
Tap a ZIP code to open it in the look-up, with a copy button for the address line.
A code can cross a county line, and one town can have several codes. The table shows the main place of each code.
"No area" means the Census Bureau draws no area for that code. Such codes are usually for post office boxes or a single building.
Places and counties: GeoNames. Areas: U.S. Census Bureau, 2024 ZIP Code Tabulation Areas. Checked in November 2026. This site is not connected with the United States Postal Service; for mailing, confirm the address with USPS.
ZIP Codes