Phone numbers in Oakland, Maryland
Oakland has 15 phone prefixes in area codes 227, 240, 301.
Biggest holders: Verizon (local phone), Onvoy, United States Cel Md. This is the local calling area (rate center) where those prefixes were first assigned.
- Mobile carrier 7%
- Local phone company 33%
- Internet / business phone carrier 40%
- Phone company 20%
Every prefix in Oakland
Search the first six digits of a number in this list. If it's here, the number started in Oakland with the carrier shown. If it isn't, check the Maryland page or look the number up.
| Prefix | Carrier | Type | Assigned |
|---|---|---|---|
| 227-272 | Onvoy | Internet / business phone carrier | 2025 |
| 240-212 | Core Communications | Internet / business phone carrier | – |
| 240-226 | Onvoy | Internet / business phone carrier | 2020 |
| 240-321 | United States Cel Md | Phone company | – |
| 240-442 | Verizon (local phone) | Local phone company | 2001 |
| 240-488 | Shentel Communications | Local phone company | 2012 |
| 240-785 | Bandwidth | Internet / business phone carrier | 2021 |
| 301-334 | Verizon (local phone) | Local phone company | – |
| 301-387 | Verizon (local phone) | Local phone company | – |
| 301-501 | AT&T Mobility | Mobile carrier | – |
| 301-533 | Verizon (local phone) | Local phone company | – |
| 301-616 | United States Cel Md | Phone company | – |
| 301-849 | Bandwidth | Internet / business phone carrier | – |
| 301-859 | Level 3 (Lumen) | Internet / business phone carrier | 2002 |
| 301-914 | Procom | Phone company | 2012 |
Most prefixes are pooled: the 10,000 numbers in each are handed out in blocks of 1,000 to different carriers, and people can also take their numbers to another carrier. So the carrier shown is where the prefix started, not a guarantee about any one number. Source: NANPA central office code records, 2026-10-10.