ZIP Code 95503 — Eureka, CA
95503 is a standard (street delivery) ZIP code serving Eureka, California, in Humboldt County. To mail something here you only need these five digits — but the four-digit extension narrows delivery to a single point, and it is what USPS bulk postage discounts are priced on.
ZIP code 95503 at a glance
| ZIP code | 95503 |
|---|---|
| Primary city | Eureka |
| State | California (CA) |
| County | Humboldt FIPS 06023 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Los_Angeles |
| Population | 25,054 |
| Coordinates | 40.724060, -124.091780 |
How ZIP+4 works in 95503
The four digits after the hyphen encode a delivery segment inside 95503. In practice one segment usually means:
- One side of one block — odd numbers on a street between two cross streets
- A single large building, or one floor of it
- A group of PO boxes, sometimes a single box
- A single business that receives enough mail to warrant its own code
That is why 95503 has no single ZIP+4: two neighbors across the street from each other usually have different ones. Enter a street address above and we will return the exact nine-digit code along with the standardized USPS address format.
Other ZIP codes in Eureka
Nearby ZIP codes
Showing the closest twelve. See every ZIP code within 25 miles of 95503.
| ZIP | City | Distance |
|---|---|---|
| 95501 | Eureka, CA | 6.1 mi |
| 95537 | Fields Landing, CA | 6.6 mi |
| 95524 | Bayside, CA | 7.2 mi |
| 95564 | Samoa, CA | 7.4 mi |
| 95551 | Loleta, CA | 7.7 mi |
| 95521 | Arcata, CA | 8.7 mi |
| 95547 | Hydesville, CA | 10.7 mi |
| 95540 | Fortuna, CA | 11 mi |
| 95549 | Kneeland, CA | 11.3 mi |
| 95550 | Korbel, CA | 14.2 mi |
| 95519 | Mckinleyville, CA | 16.3 mi |
| 95536 | Ferndale, CA | 17.3 mi |
Questions about 95503
What is the ZIP+4 code for 95503?
95503 is the five-digit ZIP code. The ZIP+4 adds four more digits that identify a specific delivery point — usually one side of a city block, a single building, or a group of PO boxes. Because those four digits change from address to address within 95503, you need to look up a specific street address to get them.
What city is 95503?
95503 is assigned to Eureka, California, in Humboldt County.
Do I need to use the ZIP+4?
It is optional for ordinary mail, but it speeds up sorting and it is required for most USPS bulk-mail postage discounts. Many address-verification and e-commerce systems also use ZIP+4 to confirm a delivery point exists.
Need thousands of these?
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