ZIP Code 51056 — Smithland, IA
51056 is a standard (street delivery) ZIP code serving Smithland, Iowa, in Woodbury 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 51056 at a glance
| ZIP code | 51056 |
|---|---|
| Primary city | Smithland |
| State | Iowa (IA) |
| County | Woodbury FIPS 19193 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Chicago |
| Population | 346 |
| Coordinates | 42.234430, -95.953910 |
How ZIP+4 works in 51056
The four digits after the hyphen encode a delivery segment inside 51056. 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 51056 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 51056.
| ZIP | City | Distance |
|---|---|---|
| 51051 | Rodney, IA | 2.2 mi |
| 51044 | Oto, IA | 5 mi |
| 51026 | Hornick, IA | 6.3 mi |
| 51015 | Climbing Hill, IA | 9.7 mi |
| 51034 | Mapleton, IA | 9.8 mi |
| 51010 | Castana, IA | 9.9 mi |
| 51004 | Anthon, IA | 10 mi |
| 51019 | Danbury, IA | 11.9 mi |
| 51063 | Whiting, IA | 13.8 mi |
| 51040 | Onawa, IA | 15.3 mi |
| 51055 | Sloan, IA | 15.8 mi |
| 51039 | Moville, IA | 16.2 mi |
Questions about 51056
What is the ZIP+4 code for 51056?
51056 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 51056, you need to look up a specific street address to get them.
What city is 51056?
51056 is assigned to Smithland, Iowa, in Woodbury 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.