ZIP Code 52231 — Harper, IA
52231 is a standard (street delivery) ZIP code serving Harper, Iowa, in Keokuk 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 52231 at a glance
| ZIP code | 52231 |
|---|---|
| Primary city | Harper |
| State | Iowa (IA) |
| County | Keokuk FIPS 19107 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Chicago |
| Population | 539 |
| Coordinates | 41.363710, -92.059120 |
How ZIP+4 works in 52231
The four digits after the hyphen encode a delivery segment inside 52231. 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 52231 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 52231.
| ZIP | City | Distance |
|---|---|---|
| 52248 | Keota, IA | 6.4 mi |
| 52335 | South English, IA | 6.6 mi |
| 52591 | Sigourney, IA | 7.6 mi |
| 52355 | Webster, IA | 9.1 mi |
| 52576 | Ollie, IA | 10.7 mi |
| 52562 | Hayesville, IA | 11.9 mi |
| 52316 | North English, IA | 12.1 mi |
| 52585 | Richland, IA | 12.6 mi |
| 52359 | West Chester, IA | 12.9 mi |
| 52356 | Wellman, IA | 13.4 mi |
| 50136 | Keswick, IA | 14 mi |
| 52308 | Millersburg, IA | 15.4 mi |
Questions about 52231
What is the ZIP+4 code for 52231?
52231 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 52231, you need to look up a specific street address to get them.
What city is 52231?
52231 is assigned to Harper, Iowa, in Keokuk 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.