ZIP Code 57521 — Belvidere, SD
57521 is a standard (street delivery) ZIP code serving Belvidere, South Dakota, in Mellette 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 57521 at a glance
| ZIP code | 57521 |
|---|---|
| Primary city | Belvidere |
| State | South Dakota (SD) |
| County | Mellette FIPS 46095 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Chicago |
| Population | 314 |
| Coordinates | 43.793490, -101.186820 |
How ZIP+4 works in 57521
The four digits after the hyphen encode a delivery segment inside 57521. 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 57521 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 57521.
| ZIP | City | Distance |
|---|---|---|
| 57562 | Okaton, SD | 13.5 mi |
| 57543 | Kadoka, SD | 17 mi |
| 57560 | Norris, SD | 24.4 mi |
| 57547 | Long Valley, SD | 24.9 mi |
| 57579 | White River, SD | 25 mi |
| 57559 | Murdo, SD | 25.2 mi |
| 57577 | Wanblee, SD | 30.1 mi |
| 57552 | Midland, SD | 32.1 mi |
| 57566 | Parmelee, SD | 33.5 mi |
| 57567 | Philip, SD | 35.3 mi |
| 57555 | Mission, SD | 43.1 mi |
Questions about 57521
What is the ZIP+4 code for 57521?
57521 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 57521, you need to look up a specific street address to get them.
What city is 57521?
57521 is assigned to Belvidere, South Dakota, in Mellette 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.