ZIP Code 51446 — Irwin, IA
51446 is a standard (street delivery) ZIP code serving Irwin, Iowa, in Shelby 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 51446 at a glance
| ZIP code | 51446 |
|---|---|
| Primary city | Irwin |
| State | Iowa (IA) |
| County | Shelby FIPS 19165 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Chicago |
| Population | 499 |
| Coordinates | 41.776630, -95.192770 |
How ZIP+4 works in 51446
The four digits after the hyphen encode a delivery segment inside 51446. 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 51446 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 51446.
| ZIP | City | Distance |
|---|---|---|
| 51447 | Kirkman, IA | 3.8 mi |
| 51454 | Manilla, IA | 7.2 mi |
| 51527 | Defiance, IA | 8.8 mi |
| 51432 | Aspinwall, IA | 9.6 mi |
| 51543 | Kimballton, IA | 10.2 mi |
| 51537 | Harlan, IA | 10.4 mi |
| 51578 | Westphalia, IA | 11.1 mi |
| 51455 | Manning, IA | 11.5 mi |
| 50110 | Gray, IA | 11.6 mi |
| 51530 | Earling, IA | 12 mi |
| 50025 | Audubon, IA | 14.1 mi |
| 51531 | Elk Horn, IA | 14.1 mi |
Questions about 51446
What is the ZIP+4 code for 51446?
51446 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 51446, you need to look up a specific street address to get them.
What city is 51446?
51446 is assigned to Irwin, Iowa, in Shelby 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.