ZIP Code 63090 — Washington, MO
63090 is a standard (street delivery) ZIP code serving Washington, Missouri, in Franklin 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 63090 at a glance
| ZIP code | 63090 |
|---|---|
| Primary city | Washington |
| State | Missouri (MO) |
| County | Franklin FIPS 29071 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Chicago |
| Population | 23,258 |
| Coordinates | 38.531760, -91.050470 |
How ZIP+4 works in 63090
The four digits after the hyphen encode a delivery segment inside 63090. 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 63090 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 63090.
| ZIP | City | Distance |
|---|---|---|
| 63084 | Union, MO | 8.1 mi |
| 63357 | Marthasville, MO | 8.8 mi |
| 63013 | Beaufort, MO | 9.6 mi |
| 63332 | Augusta, MO | 9.8 mi |
| 63089 | Villa Ridge, MO | 10.4 mi |
| 63068 | New Haven, MO | 10.8 mi |
| 63055 | Labadie, MO | 11.5 mi |
| 63039 | Gray Summit, MO | 11.9 mi |
| 63056 | Leslie, MO | 13.4 mi |
| 63077 | Saint Clair, MO | 14.6 mi |
| 63073 | Saint Albans, MO | 15.6 mi |
| 63341 | Defiance, MO | 15.6 mi |
Questions about 63090
What is the ZIP+4 code for 63090?
63090 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 63090, you need to look up a specific street address to get them.
What city is 63090?
63090 is assigned to Washington, Missouri, in Franklin 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.