ZIP Code 57223 — Castlewood, SD
57223 is a standard (street delivery) ZIP code serving Castlewood, South Dakota, in Hamlin 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 57223 at a glance
| ZIP code | 57223 |
|---|---|
| Primary city | Castlewood |
| State | South Dakota (SD) |
| County | Hamlin FIPS 46057 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Chicago |
| Population | 1,429 |
| Coordinates | 44.710190, -97.005670 |
How ZIP+4 works in 57223
The four digits after the hyphen encode a delivery segment inside 57223. 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 57223 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 57223.
| ZIP | City | Distance |
|---|---|---|
| 57234 | Estelline, SD | 9.4 mi |
| 57241 | Hayti, SD | 10.4 mi |
| 57248 | Lake Norden, SD | 12.8 mi |
| 57238 | Goodwin, SD | 13.2 mi |
| 57245 | Kranzburg, SD | 13.4 mi |
| 57226 | Clear Lake, SD | 14.8 mi |
| 57201 | Watertown, SD | 16 mi |
| 57220 | Bruce, SD | 17.8 mi |
| 57242 | Hazel, SD | 17.9 mi |
| 57268 | Toronto, SD | 18.4 mi |
| 57214 | Badger, SD | 18.6 mi |
| 57218 | Brandt, SD | 20.4 mi |
Questions about 57223
What is the ZIP+4 code for 57223?
57223 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 57223, you need to look up a specific street address to get them.
What city is 57223?
57223 is assigned to Castlewood, South Dakota, in Hamlin 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.