| Code | Name | Region |
|---|---|---|
| USNMX | Nome | TX |
| USNNL | Nondalton | AK |
| USKKE | Nooksack | WA |
| USNOO | Noonan | ND |
| USORV | Noorvik | AK |
| USOIU | Nora Springs | IA |
| USNQO | Norco | CA |
| USNCM | Norco | LA |
| USUXN | Norcross | GA |
| USNS9 | Norcross | MN |
| USNCX | Norcross | VA |
| USNIY | Ninety Six | SC |
| USN2E | Nineveh | IN |
| USNIN | Ninilchik | AK |
| USNN3 | Ninnekah | OK |
| USN5B | Niobrara | NE |
| USNIA | Niota | TN |
| USNIO | Nipomo | CA |
| USNP5 | Nipton | CA |
| USIYF | Niskayuna | NY |
| USNIT | Nitro | WV |
| USN2W | Niwot | CO |
| USNXI | Nixa | MO |
| USNIX | Nixon | PA |
| USX8N | Nixon | TX |
| USNK3 | Noank | CT |
| USWTK | Noatak | AK |
| USNO9 | Noble | IL |
| USOBL | Noble | OK |
| US8NO | Nobleboro | ME |
| USNVB | Noblesville | IN |
| USNCL | Nichols | SC |
| USIHU | Nichols | WI |
| USNH6 | Nichols Hills | OK |
| USNS3 | Nichols, Tioga | NY |
| USNI8 | Nicholson | MS |
| USNI7 | Nicholson | PA |
| USNV3 | Nickelsville | VA |
| USNQL | Nicollet | MN |
| USNIH | Nighthawk | WA |
| USNME | Nightmute | AK |
| USNQK | Nikishka | AK |
| USNIK | Nikiski | AK |
| USNIB | Nikolai | AK |
| USIKO | Nikolski | AK |
| USNNQ | Niland | CA |
| USNIZ | Niles | CA |
| USNIL | Niles | IL |
| USNLE | Niles | MI |
| USNLS | Niles | OH |