ZIP Code 78598 — Port Mansfield, TX
78598 is a standard (street delivery) ZIP code serving Port Mansfield, Texas, in Willacy 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 78598 at a glance
| ZIP code | 78598 |
|---|---|
| Primary city | Port Mansfield |
| State | Texas (TX) |
| County | Willacy FIPS 48489 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Chicago |
| Population | 245 |
| Coordinates | 26.523630, -97.423270 |
How ZIP+4 works in 78598
The four digits after the hyphen encode a delivery segment inside 78598. 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 78598 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 78598.
| ZIP | City | Distance |
|---|---|---|
| 78590 | San Perlita, TX | 13.1 mi |
| 78583 | Rio Hondo, TX | 16.9 mi |
| 78580 | Raymondville, TX | 20.3 mi |
| 78569 | Lyford, TX | 22 mi |
| 78597 | South Padre Island, TX | 23.6 mi |
| 78550 | Harlingen, TX | 23.8 mi |
| 78594 | Sebastian, TX | 26.5 mi |
| 78535 | Combes, TX | 26.8 mi |
| 78566 | Los Fresnos, TX | 26.8 mi |
| 78593 | Santa Rosa, TX | 30.2 mi |
| 78552 | Harlingen, TX | 30.3 mi |
| 78338 | Armstrong, TX | 30.6 mi |
Questions about 78598
What is the ZIP+4 code for 78598?
78598 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 78598, you need to look up a specific street address to get them.
What city is 78598?
78598 is assigned to Port Mansfield, Texas, in Willacy 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.