ZIP Code 51527 — Defiance, IA
51527 is a standard (street delivery) ZIP code serving Defiance, 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 51527 at a glance
| ZIP code | 51527 |
|---|---|
| Primary city | Defiance |
| State | Iowa (IA) |
| County | Shelby FIPS 19165 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Chicago |
| Population | 362 |
| Coordinates | 41.828750, -95.348000 |
How ZIP+4 works in 51527
The four digits after the hyphen encode a delivery segment inside 51527. 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 51527 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 51527.
| ZIP | City | Distance |
|---|---|---|
| 51530 | Earling, IA | 5.1 mi |
| 51578 | Westphalia, IA | 7.9 mi |
| 51454 | Manilla, IA | 8.1 mi |
| 51446 | Irwin, IA | 8.8 mi |
| 51528 | Dow City, IA | 10.4 mi |
| 51562 | Panama, IA | 10.6 mi |
| 51447 | Kirkman, IA | 10.9 mi |
| 51520 | Arion, IA | 11.3 mi |
| 51432 | Aspinwall, IA | 12.2 mi |
| 51537 | Harlan, IA | 12.9 mi |
| 51442 | Denison, IA | 13.7 mi |
| 51529 | Dunlap, IA | 14.5 mi |
Questions about 51527
What is the ZIP+4 code for 51527?
51527 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 51527, you need to look up a specific street address to get them.
What city is 51527?
51527 is assigned to Defiance, 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.