ZIP Code 59638 — Jefferson City, MT
59638 is a standard (street delivery) ZIP code serving Jefferson City, 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 59638 at a glance
| ZIP code | 59638 |
|---|---|
| Primary city | Jefferson City |
| State | Montana (MT) |
| County | Jefferson FIPS 30043 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Denver |
| Population | 769 |
| Coordinates | 46.357900, -112.027720 |
How ZIP+4 works in 59638
The four digits after the hyphen encode a delivery segment inside 59638. 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 59638 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 59638.
| ZIP | City | Distance |
|---|---|---|
| 59634 | Clancy, MT | 5.4 mi |
| 59632 | Boulder, MT | 13.4 mi |
| 59601 | Helena, MT | 14.5 mi |
| 59623 | Helena, MT | 16 mi |
| 59625 | Helena, MT | 16.8 mi |
| 59635 | East Helena, MT | 16.9 mi |
| 59631 | Basin, MT | 17.7 mi |
| 59636 | Fort Harrison, MT | 18.3 mi |
| 59647 | Winston, MT | 19.4 mi |
| 59728 | Elliston, MT | 20.9 mi |
| 59643 | Toston, MT | 26.4 mi |
| 59602 | Helena, MT | 26.7 mi |
Questions about 59638
What is the ZIP+4 code for 59638?
59638 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 59638, you need to look up a specific street address to get them.
What city is 59638?
59638 is assigned to Jefferson City, 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.