Phone numbers in Hillsboro, Maryland
Hillsboro has 3 phone prefixes in area codes 410, 667.
Biggest holders: Onvoy, Verizon (local phone). This is the local calling area (rate center) where those prefixes were first assigned.
- Local phone company 33%
- Internet / business phone carrier 67%
Every prefix in Hillsboro
Search the first six digits of a number in this list. If it's here, the number started in Hillsboro with the carrier shown. If it isn't, check the Maryland page or look the number up.
| Prefix | Carrier | Type | Assigned |
|---|---|---|---|
| 410-364 | Verizon (local phone) | Local phone company | – |
| 667-255 | Onvoy | Internet / business phone carrier | 2018 |
| 667-665 | Onvoy | Internet / business phone carrier | 2021 |
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.