| Code | Name | Region |
|---|---|---|
| USOB2 | Oak Bluffs | MA |
| USQHO | Oak Brook | IL |
| USOCK | Oak Creek | CO |
| USOAC | Oak Creek | WI |
| USOFR | Oak Forest | IL |
| USQOG | Oak Grove | IL |
| USOGK | Oak Grove | LA |
| USIKG | Oak Grove | MO |
| USOGR | Oak Grove | OR |
| USAKJ | Oak Grove | VA |
| USOHO | Oak Harbor | OH |
| USNT4 | Nottingham | NH |
| USNHG | Nottingham | PA |
| USNT9 | Notus | ID |
| USXJP | Nova | OH |
| USNOT | Novato | CA |
| USOVV | Novelty | MO |
| USZGW | Novelty | OH |
| USNOV | Novi | MI |
| USNTK | Nowata | OK |
| USNXP | Noxapater | MS |
| USNOY | Noyes | MN |
| USNUA | Nucla | CO |
| USNUE | Nuevo | CA |
| USNUI | Nuiqsut | AK |
| USNUL | Nulato | AK |
| USNUP | Nunapitchuk | AK |
| USNXN | Nunda | NY |
| USNZ9 | Nunica | MI |
| USVUN | Nunn | CO |
| USNLL | Nunnelly | TN |
| USORQ | Norwalk | CT |
| USNKJ | Norwalk | IA |
| USXJR | Norwalk | OH |
| USNJO | Norway | IA |
| USN4Y | Norway | ME |
| USNZO | Norway | MI |
| USNOW | Norwell | MA |
| USNOC | Norwich | CT |
| USNW5 | Norwich | KS |
| USOIC | Norwich | NY |
| USNQW | Norwich | VT |
| USOWD | Norwood | MA |
| USYNW | Norwood | MN |
| USNXO | Norwood | NC |
| USNRD | Norwood | NJ |
| USZNO | Norwood | NY |
| USNDY | Norwood | OH |
| USNXL | Norwood | PA |
| USTXQ | Noti | OR |