ZIP Code 59231 — Saint Marie, MT
59231 is a standard (street delivery) ZIP code serving Saint Marie, Montana, in Valley 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 59231 at a glance
| ZIP code | 59231 |
|---|---|
| Primary city | Saint Marie |
| State | Montana (MT) |
| County | Valley FIPS 30105 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Denver |
| Population | 306 |
| Coordinates | 48.403950, -106.544110 |
How ZIP+4 works in 59231
The four digits after the hyphen encode a delivery segment inside 59231. 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 59231 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 59231.
| ZIP | City | Distance |
|---|---|---|
| 59248 | Nashua, MT | 15.8 mi |
| 59244 | Larslan, MT | 18.8 mi |
| 59273 | Vandalia, MT | 19.5 mi |
| 59241 | Hinsdale, MT | 23.3 mi |
| 59230 | Glasgow, MT | 24.1 mi |
| 59225 | Frazer, MT | 27.5 mi |
| 59250 | Opheim, MT | 32.3 mi |
| 59240 | Glentana, MT | 33.3 mi |
| 59260 | Richland, MT | 36.3 mi |
Questions about 59231
What is the ZIP+4 code for 59231?
59231 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 59231, you need to look up a specific street address to get them.
What city is 59231?
59231 is assigned to Saint Marie, Montana, in Valley 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.