| N |
Non Postal Community Name: Former Postal Facility |
| P |
Post Office: An official post office branch. |
| U |
Urbanization: A postal designation specific to Puerto Rico. |
| B |
Branch: A postal facility that is not the main post office and is outside the corporate limits of a city. |
| A |
Airport Mail Facility: Facilities through which US mail is flown in and out of a city. |
| C |
Community Post Office: a contract postal unit providing mail services to small communities. |
| S |
Station: A post office that is not the main office for a city but is in corporate city limits. |
| K |
Bulk Mail Center: Centers that handle bulk mail. Typically commercial, business and advertising mail. |