ZIP Code 57445 — Groton, SD
57445 is a standard (street delivery) ZIP code serving Groton, South Dakota, in Brown 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 57445 at a glance
| ZIP code | 57445 |
|---|---|
| Primary city | Groton |
| State | South Dakota (SD) |
| County | Brown FIPS 46013 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Chicago |
| Population | 2,072 |
| Coordinates | 45.458280, -98.120940 |
How ZIP+4 works in 57445
The four digits after the hyphen encode a delivery segment inside 57445. 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 57445 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 57445.
| ZIP | City | Distance |
|---|---|---|
| 57439 | Ferney, SD | 8.6 mi |
| 57427 | Bath, SD | 9.7 mi |
| 57422 | Andover, SD | 9.9 mi |
| 57474 | Stratford, SD | 14.1 mi |
| 57433 | Columbia, SD | 16 mi |
| 57432 | Claremont, SD | 16.3 mi |
| 57468 | Pierpont, SD | 18 mi |
| 57479 | Warner, SD | 18.7 mi |
| 57449 | Houghton, SD | 19 mi |
| 57219 | Bristol, SD | 19.5 mi |
| 57454 | Langford, SD | 19.9 mi |
| 57401 | Aberdeen, SD | 19.9 mi |
Questions about 57445
What is the ZIP+4 code for 57445?
57445 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 57445, you need to look up a specific street address to get them.
What city is 57445?
57445 is assigned to Groton, South Dakota, in Brown 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.