ZIP Code 51240 — Inwood, IA
51240 is a standard (street delivery) ZIP code serving Inwood, Iowa, in Lyon 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 51240 at a glance
| ZIP code | 51240 |
|---|---|
| Primary city | Inwood |
| State | Iowa (IA) |
| County | Lyon FIPS 19119 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Chicago |
| Population | 1,914 |
| Coordinates | 43.309860, -96.457270 |
How ZIP+4 works in 51240
The four digits after the hyphen encode a delivery segment inside 51240. 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 51240 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 51240.
| ZIP | City | Distance |
|---|---|---|
| 51230 | Alvord, IA | 7.5 mi |
| 57027 | Fairview, SD | 8.4 mi |
| 57013 | Canton, SD | 8.4 mi |
| 51241 | Larchwood, IA | 9.7 mi |
| 51247 | Rock Valley, IA | 10.1 mi |
| 51242 | Lester, IA | 10.4 mi |
| 51235 | Doon, IA | 12.2 mi |
| 57034 | Hudson, SD | 13.5 mi |
| 57032 | Harrisburg, SD | 13.9 mi |
| 57077 | Worthing, SD | 15.1 mi |
| 56138 | Hills, MN | 15.8 mi |
| 51246 | Rock Rapids, IA | 16.7 mi |
Questions about 51240
What is the ZIP+4 code for 51240?
51240 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 51240, you need to look up a specific street address to get them.
What city is 51240?
51240 is assigned to Inwood, Iowa, in Lyon 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.