ZIP Code 98240 — Custer, WA
98240 is a standard (street delivery) ZIP code serving Custer, Washington, in Whatcom 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 98240 at a glance
| ZIP code | 98240 |
|---|---|
| Primary city | Custer |
| State | Washington (WA) |
| County | Whatcom FIPS 53073 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Los_Angeles |
| Population | 3,593 |
| Coordinates | 48.947110, -122.620610 |
How ZIP+4 works in 98240
The four digits after the hyphen encode a delivery segment inside 98240. 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 98240 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.
Nearby ZIP codes
Showing the closest twelve. See every ZIP code within 25 miles of 98240.
| ZIP | City | Distance |
|---|---|---|
| 98230 | Blaine, WA | 4 mi |
| 98248 | Ferndale, WA | 5.7 mi |
| 98264 | Lynden, WA | 7.4 mi |
| 98226 | Bellingham, WA | 13.5 mi |
| 98276 | Nooksack, WA | 13.6 mi |
| 98247 | Everson, WA | 14.1 mi |
| 98225 | Bellingham, WA | 14.3 mi |
| 98262 | Lummi Island, WA | 17.6 mi |
| 98295 | Sumas, WA | 18.2 mi |
| 98229 | Bellingham, WA | 19.8 mi |
| 98281 | Point Roberts, WA | 20 mi |
| 98279 | Olga, WA | 22.5 mi |
Questions about 98240
What is the ZIP+4 code for 98240?
98240 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 98240, you need to look up a specific street address to get them.
What city is 98240?
98240 is assigned to Custer, Washington, in Whatcom 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?
Upload a CSV and get ZIP+4, county, carrier route, and delivery-point data appended to every row — or call the API directly.