ZIP Code 57661 — Whitehorse, SD
57661 is a standard (street delivery) ZIP code serving Whitehorse, South Dakota, in Dewey 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 57661 at a glance
| ZIP code | 57661 |
|---|---|
| Primary city | Whitehorse |
| State | South Dakota (SD) |
| County | Dewey FIPS 46041 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Denver |
| Population | 177 |
| Coordinates | 45.270050, -100.964330 |
How ZIP+4 works in 57661
The four digits after the hyphen encode a delivery segment inside 57661. 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 57661 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 57661.
| ZIP | City | Distance |
|---|---|---|
| 57630 | Glencross, SD | 7.3 mi |
| 57656 | Timber Lake, SD | 12.7 mi |
| 57652 | Ridgeview, SD | 16.2 mi |
| 57657 | Trail City, SD | 19.2 mi |
| 57625 | Eagle Butte, SD | 21.7 mi |
| 57601 | Mobridge, SD | 23 mi |
| 57633 | Isabel, SD | 28.7 mi |
| 57636 | Lantry, SD | 29 mi |
| 57639 | Little Eagle, SD | 29.3 mi |
| 57658 | Wakpala, SD | 33.2 mi |
| 57621 | Bullhead, SD | 34.9 mi |
Questions about 57661
What is the ZIP+4 code for 57661?
57661 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 57661, you need to look up a specific street address to get them.
What city is 57661?
57661 is assigned to Whitehorse, South Dakota, in Dewey 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.