ZIP Code 99403 — Clarkston, WA
99403 is a standard (street delivery) ZIP code serving Clarkston, Washington, in Asotin 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 99403 at a glance
| ZIP code | 99403 |
|---|---|
| Primary city | Clarkston |
| State | Washington (WA) |
| County | Asotin FIPS 53003 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Los_Angeles |
| Population | 20,760 |
| Coordinates | 46.381140, -117.259740 |
How ZIP+4 works in 99403
The four digits after the hyphen encode a delivery segment inside 99403. 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 99403 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 99403.
| ZIP | City | Distance |
|---|---|---|
| 99179 | Uniontown, WA | 10.6 mi |
| 99402 | Asotin, WA | 14.4 mi |
| 99113 | Colton, WA | 14.5 mi |
| 99347 | Pomeroy, WA | 15.1 mi |
| 83501 | Lewiston, ID | 19.9 mi |
| 99401 | Anatone, WA | 20.1 mi |
| 83832 | Genesee, ID | 20.5 mi |
| 83540 | Lapwai, ID | 22.8 mi |
| 99163 | Pullman, WA | 24 mi |
| 83844 | Moscow, ID | 26.5 mi |
| 83535 | Juliaetta, ID | 27.7 mi |
| 83843 | Moscow, ID | 28 mi |
Questions about 99403
What is the ZIP+4 code for 99403?
99403 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 99403, you need to look up a specific street address to get them.
What city is 99403?
99403 is assigned to Clarkston, Washington, in Asotin 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.