Troy Montana Area Code
One area code covers Troy: 406.
The code covering Troy
| Area code | Primarily serves | In service |
|---|---|---|
| 406 | Billings | 1947 |
Scope the codes matched to Troy. Source geoinfo-dataset (full_dataset) ZIP→NPA (2018 snapshot) and LocalCallingGuide NPA list (2026-07 NPA list). Updated . Overlay relationships come from the numbering-plan authority; the place match is computed.
Which part of town has which code
Troy has a single code, so there is nothing to divide — every local line carries 406.
ZIP codes for the same city
Postal geography is organised separately from telephone geography, so Troy’s 1 ZIP code do not map onto the codes above. They are listed in full, with the county each falls in, on the postal side of the site.