Post Offices List in Jefferson County, Montana:
| Basin Post Office | 100 Basin St, Basin, MT 59631 |
| Boulder Post Office | 126 S Main St, Boulder, MT 59632 |
| Clancy Post Office | 2 N Main St, Clancy, MT 59634 |
| Jefferson City Post Office | 1 N Main St, Jefferson City, MT 59638 |
| Whitehall Post Office | 15 N Main St, Whitehall, MT 59759 |