| Zip Code | City | Population ↓ |
|---|---|---|
| 59405 | Great Falls | 34,010 |
| 59404 | Great Falls | 28,417 |
| 59401 | Great Falls | 13,660 |
| 59421 | Cascade | 2,025 |
| 59412 | Belt | 1,493 |
| 59487 | Vaughn | 1,394 |
| 59485 | Ulm | 712 |
| 59414 | Black Eagle | 672 |
| 59472 | Sand Coulee | 541 |
| 59443 | Fort Shaw | 498 |
| 59483 | Sun River | 358 |
| 59477 | Simms | 329 |
| 59480 | Stockett | 303 |
| 59463 | Monarch | 103 |
| 59465 | Neihart | 40 |
The data shown reflect ZCTAs from the US Census. As of 2024, there are 15 ZCTAs in Cascade County, Montana (US Census).