ZIP Code 59631 — Basin, MT
59631 is a standard (street delivery) ZIP code serving Basin, Montana, in Jefferson 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 59631 at a glance
| ZIP code | 59631 |
|---|---|
| Primary city | Basin |
| State | Montana (MT) |
| County | Jefferson FIPS 30043 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Denver |
| Population | 375 |
| Coordinates | 46.291680, -112.386870 |
How ZIP+4 works in 59631
The four digits after the hyphen encode a delivery segment inside 59631. 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 59631 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 59631.
| ZIP | City | Distance |
|---|---|---|
| 59728 | Elliston, MT | 14.8 mi |
| 59638 | Jefferson City, MT | 17.7 mi |
| 59701 | Butte, MT | 18.1 mi |
| 59722 | Deer Lodge, MT | 18.1 mi |
| 59601 | Helena, MT | 20 mi |
| 59632 | Boulder, MT | 20.4 mi |
| 59634 | Clancy, MT | 20.5 mi |
| 59748 | Ramsay, MT | 22.5 mi |
| 59756 | Warm Springs, MT | 22.8 mi |
| 59636 | Fort Harrison, MT | 25.9 mi |
| 59623 | Helena, MT | 26.4 mi |
| 59731 | Garrison, MT | 27 mi |
Questions about 59631
What is the ZIP+4 code for 59631?
59631 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 59631, you need to look up a specific street address to get them.
What city is 59631?
59631 is assigned to Basin, Montana, in Jefferson 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.