| Zip Code | City | Population ↓ |
|---|---|---|
| 3246 | Laconia | 16,943 |
| 3249 | Gilford | 7,725 |
| 3220 | Belmont | 7,454 |
| 3253 | Meredith | 6,701 |
| 3809 | Alton | 3,617 |
| 3225 | Center Barnstead | 3,406 |
| 3269 | Sanbornton | 2,957 |
| 3256 | New Hampton | 2,591 |
| 3237 | Gilmanton | 2,338 |
| 3810 | Alton Bay | 2,286 |
| 3837 | Gilmanton Iron Works | 1,622 |
| 3218 | Barnstead | 1,535 |
| 3226 | Center Harbor | 820 |
The data shown reflect ZCTAs from the US Census. As of 2024, there are 13 ZCTAs in Belknap County, New Hampshire (US Census).