ZIP Code 51640 — Hamburg, IA
51640 is a standard (street delivery) ZIP code serving Hamburg, Iowa, in Fremont 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 51640 at a glance
| ZIP code | 51640 |
|---|---|
| Primary city | Hamburg |
| State | Iowa (IA) |
| County | Fremont FIPS 19071 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Chicago |
| Population | 1,381 |
| Coordinates | 40.622620, -95.663400 |
How ZIP+4 works in 51640
The four digits after the hyphen encode a delivery segment inside 51640. 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 51640 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 51640.
| ZIP | City | Distance |
|---|---|---|
| 51650 | Riverton, IA | 6.9 mi |
| 64496 | Watson, MO | 9 mi |
| 68421 | Peru, NE | 10 mi |
| 51652 | Sidney, IA | 10.4 mi |
| 51648 | Percival, IA | 11 mi |
| 68410 | Nebraska City, NE | 11.7 mi |
| 51639 | Farragut, IA | 11.9 mi |
| 68379 | Julian, NE | 12.6 mi |
| 64482 | Rock Port, MO | 13.3 mi |
| 51654 | Thurman, IA | 15.2 mi |
| 68321 | Brownville, NE | 15.8 mi |
| 51647 | Northboro, IA | 16.7 mi |
Questions about 51640
What is the ZIP+4 code for 51640?
51640 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 51640, you need to look up a specific street address to get them.
What city is 51640?
51640 is assigned to Hamburg, Iowa, in Fremont 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.