| Locality | Post Code |
|---|---|
| Nakadate (筑西市) | 308-0005 |
| Nakamurashinden (筑西市) | 308-0108 |
| Nakane (筑西市) | 300-4513 |
| Nakaueno (筑西市) | 300-4524 |
| Naoi (筑西市) | 308-0803 |
| Narita (筑西市) | 308-0821 |
| Narui (筑西市) | 300-4533 |
| Nekoshima (筑西市) | 300-4501 |
| Niginari (筑西市) | 308-0841 |
| Niihari (筑西市) | 309-1106 |
| Nishiho (筑西市) | 308-0845 |
| Nishihozue (筑西市) | 308-0105 |
| Nishiishida (筑西市) | 308-0834 |
| Nishioshima (筑西市) | 308-0062 |
| Nishiyagai (筑西市) | 308-0054 |
| Nishiyamada (筑西市) | 308-0867 |
| Nishiyono (筑西市) | 308-0832 |
| No (筑西市) | 308-0016 |
| Noda (筑西市) | 308-0833 |
| Nodono (筑西市) | 308-0843 |
| Nunogawa (筑西市) | 308-0846 |
| Obayashi (筑西市) | 300-4537, 308-0806 |
| Ochiai (筑西市) | 308-0002 |
| Ogawa (筑西市) | 308-0857 |
| Oguri (筑西市) | 309-1101 |
| Okazeri (筑西市) | 308-0051 |