ZIP Code 73503 — Fort Sill, OK
73503 is a standard (street delivery) ZIP code serving Fort Sill, Oklahoma, in Comanche 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 73503 at a glance
| ZIP code | 73503 |
|---|---|
| Primary city | Fort Sill |
| State | Oklahoma (OK) |
| County | Comanche FIPS 40031 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Chicago |
| Population | 11,468 |
| Coordinates | 34.673480, -98.496490 |
How ZIP+4 works in 73503
The four digits after the hyphen encode a delivery segment inside 73503. 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 73503 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 73503.
| ZIP | City | Distance |
|---|---|---|
| 73557 | Medicine Park, OK | 4 mi |
| 73507 | Lawton, OK | 5.2 mi |
| 73505 | Lawton, OK | 7.1 mi |
| 73527 | Cache, OK | 10.2 mi |
| 73538 | Elgin, OK | 11.7 mi |
| 73501 | Lawton, OK | 14.2 mi |
| 73540 | Faxon, OK | 14.4 mi |
| 73552 | Indiahoma, OK | 15.1 mi |
| 73543 | Geronimo, OK | 15.8 mi |
| 73006 | Apache, OK | 16.8 mi |
| 73567 | Sterling, OK | 19.2 mi |
| 73541 | Fletcher, OK | 19.7 mi |
Questions about 73503
What is the ZIP+4 code for 73503?
73503 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 73503, you need to look up a specific street address to get them.
What city is 73503?
73503 is assigned to Fort Sill, Oklahoma, in Comanche 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.