Phone numbers in Cambridge, Maryland
Cambridge has 16 phone prefixes in area codes 410, 443, 667.
Biggest holders: Verizon Wireless, Verizon (local phone), Core Communications. This is the local calling area (rate center) where those prefixes were first assigned.
- Mobile carrier 44%
- Local phone company 19%
- Internet / business phone carrier 38%
Every prefix in Cambridge
Search the first six digits of a number in this list. If it's here, the number started in Cambridge with the carrier shown. If it isn't, check the Maryland page or look the number up.
| Prefix | Carrier | Type | Assigned |
|---|---|---|---|
| 410-221 | Verizon (local phone) | Local phone company | – |
| 410-228 | Verizon (local phone) | Local phone company | – |
| 410-330 | AT&T Mobility | Mobile carrier | – |
| 410-901 | Verizon (local phone) | Local phone company | – |
| 443-205 | Verizon Wireless | Mobile carrier | – |
| 443-225 | MetroPCS (T-Mobile) | Mobile carrier | 2004 |
| 443-382 | Core Communications | Internet / business phone carrier | – |
| 443-477 | Verizon Wireless | Mobile carrier | 2007 |
| 443-515 | Verizon Wireless | Mobile carrier | 2009 |
| 443-521 | Verizon Wireless | Mobile carrier | – |
| 443-972 | Windstream (PAETEC) | Internet / business phone carrier | 2011 |
| 667-327 | Onvoy | Internet / business phone carrier | 2021 |
| 667-343 | MCImetro (Verizon Business) | Internet / business phone carrier | 2021 |
| 667-372 | Core Communications | Internet / business phone carrier | 2018 |
| 667-389 | Commio | Internet / business phone carrier | – |
| 667-485 | Verizon Wireless | Mobile carrier | 2024 |
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.