ZIP Code 66538 — Seneca, KS
66538 is a standard (street delivery) ZIP code serving Seneca, Kansas, in Nemaha 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 66538 at a glance
| ZIP code | 66538 |
|---|---|
| Primary city | Seneca |
| State | Kansas (KS) |
| County | Nemaha FIPS 20131 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Chicago |
| Population | 3,602 |
| Coordinates | 39.849420, -96.045910 |
How ZIP+4 works in 66538
The four digits after the hyphen encode a delivery segment inside 66538. 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 66538 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 66538.
| ZIP | City | Distance |
|---|---|---|
| 66522 | Oneida, KS | 5.8 mi |
| 66404 | Baileyville, KS | 7.1 mi |
| 66408 | Bern, KS | 8.1 mi |
| 66534 | Sabetha, KS | 11.3 mi |
| 66415 | Centralia, KS | 12 mi |
| 66403 | Axtell, KS | 12.4 mi |
| 68345 | Du Bois, NE | 13 mi |
| 66417 | Corning, KS | 13.4 mi |
| 66428 | Goff, KS | 13.5 mi |
| 66544 | Vermillion, KS | 16.6 mi |
| 66425 | Fairview, KS | 17.3 mi |
| 66550 | Wetmore, KS | 17.9 mi |
Questions about 66538
What is the ZIP+4 code for 66538?
66538 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 66538, you need to look up a specific street address to get them.
What city is 66538?
66538 is assigned to Seneca, Kansas, in Nemaha 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.