ZIP Code 51009 — Calumet, IA
51009 is a standard (street delivery) ZIP code serving Calumet, Iowa, in O'Brien 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 51009 at a glance
| ZIP code | 51009 |
|---|---|
| Primary city | Calumet |
| State | Iowa (IA) |
| County | O'Brien FIPS 19141 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Chicago |
| Population | 113 |
| Coordinates | 42.944990, -95.551420 |
How ZIP+4 works in 51009
The four digits after the hyphen encode a delivery segment inside 51009. 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 51009 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 51009.
| ZIP | City | Distance |
|---|---|---|
| 51029 | Larrabee, IA | 4.1 mi |
| 51058 | Sutherland, IA | 5 mi |
| 51046 | Paullina, IA | 6.6 mi |
| 51037 | Meriden, IA | 9.4 mi |
| 51245 | Primghar, IA | 9.5 mi |
| 51047 | Peterson, IA | 9.8 mi |
| 51014 | Cleghorn, IA | 13.7 mi |
| 51012 | Cherokee, IA | 13.8 mi |
| 51231 | Archer, IA | 14.7 mi |
| 51022 | Granville, IA | 15.1 mi |
| 51033 | Linn Grove, IA | 15.2 mi |
| 51357 | Royal, IA | 15.6 mi |
Questions about 51009
What is the ZIP+4 code for 51009?
51009 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 51009, you need to look up a specific street address to get them.
What city is 51009?
51009 is assigned to Calumet, Iowa, in O'Brien 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.