ZIP Code 51537 — Harlan, IA
51537 is a standard (street delivery) ZIP code serving Harlan, 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 51537 at a glance
| ZIP code | 51537 |
|---|---|
| Primary city | Harlan |
| State | Iowa (IA) |
| County | Shelby FIPS 19165 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Chicago |
| Population | 6,382 |
| Coordinates | 41.646460, -95.295310 |
How ZIP+4 works in 51537
The four digits after the hyphen encode a delivery segment inside 51537. 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 51537 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 51537.
| ZIP | City | Distance |
|---|---|---|
| 51578 | Westphalia, IA | 7.2 mi |
| 51447 | Kirkman, IA | 7.4 mi |
| 51446 | Irwin, IA | 10.4 mi |
| 51531 | Elk Horn, IA | 11.4 mi |
| 51543 | Kimballton, IA | 11.5 mi |
| 51530 | Earling, IA | 11.6 mi |
| 51521 | Avoca, IA | 11.8 mi |
| 51565 | Portsmouth, IA | 11.8 mi |
| 51562 | Panama, IA | 12 mi |
| 51570 | Shelby, IA | 12.1 mi |
| 51527 | Defiance, IA | 12.9 mi |
| 51577 | Walnut, IA | 13.4 mi |
Questions about 51537
What is the ZIP+4 code for 51537?
51537 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 51537, you need to look up a specific street address to get them.
What city is 51537?
51537 is assigned to Harlan, 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.