ZIP Code 51433 — Auburn, IA
51433 is a standard (street delivery) ZIP code serving Auburn, Iowa, in Sac 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 51433 at a glance
| ZIP code | 51433 |
|---|---|
| Primary city | Auburn |
| State | Iowa (IA) |
| County | Sac FIPS 19161 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Chicago |
| Population | 567 |
| Coordinates | 42.276350, -94.870570 |
How ZIP+4 works in 51433
The four digits after the hyphen encode a delivery segment inside 51433. 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 51433 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 51433.
| ZIP | City | Distance |
|---|---|---|
| 51449 | Lake City, IA | 7 mi |
| 51450 | Lake View, IA | 8.4 mi |
| 51436 | Breda, IA | 9.7 mi |
| 50561 | Lytton, IA | 10.1 mi |
| 51451 | Lanesboro, IA | 11 mi |
| 51452 | Lidderdale, IA | 11.5 mi |
| 51466 | Wall Lake, IA | 11.7 mi |
| 50583 | Sac City, IA | 12.2 mi |
| 50579 | Rockwell City, IA | 14.5 mi |
| 51401 | Carroll, IA | 14.6 mi |
| 51430 | Arcadia, IA | 15.3 mi |
| 50551 | Jolley, IA | 15.4 mi |
Questions about 51433
What is the ZIP+4 code for 51433?
51433 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 51433, you need to look up a specific street address to get them.
What city is 51433?
51433 is assigned to Auburn, Iowa, in Sac 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.