Phone numbers in Highfield-Cascade, Maryland
Highfield-Cascade has 5 phone prefixes in area codes 240, 301.
Biggest holders: Onvoy, Core Communications, Bandwidth. This is the local calling area (rate center) where those prefixes were first assigned.
- Mobile carrier 20%
- Local phone company 20%
- Internet / business phone carrier 60%
Every prefix in Highfield-Cascade
Search the first six digits of a number in this list. If it's here, the number started in Highfield-Cascade with the carrier shown. If it isn't, check the Maryland page or look the number up.
| Prefix | Carrier | Type | Assigned |
|---|---|---|---|
| 240-202 | Onvoy | Internet / business phone carrier | 2020 |
| 240-251 | Core Communications | Internet / business phone carrier | – |
| 240-617 | Bandwidth | Internet / business phone carrier | 2015 |
| 240-914 | Boost / Virgin Mobile | Mobile carrier | 2022 |
| 301-241 | Verizon (local phone) | Local phone company | – |
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.