Phone numbers in Baltimore, Ohio
Baltimore has 6 phone prefixes in area codes 220, 740.
Biggest holders: AT&T Mobility, Onvoy, Charter / Spectrum. This is the local calling area (rate center) where those prefixes were first assigned.
- Mobile carrier 50%
- Local phone company 17%
- Internet / business phone carrier 33%
Every prefix in Baltimore
Search the first six digits of a number in this list. If it's here, the number started in Baltimore with the carrier shown. If it isn't, check the Ohio page or look the number up.
| Prefix | Carrier | Type | Assigned |
|---|---|---|---|
| 220-204 | AT&T Mobility | Mobile carrier | 2020 |
| 220-269 | AT&T Mobility | Mobile carrier | 2024 |
| 220-666 | Onvoy | Internet / business phone carrier | 2017 |
| 740-400 | Charter / Spectrum | Internet / business phone carrier | 2006 |
| 740-556 | AT&T Mobility | Mobile carrier | 2022 |
| 740-862 | Frontier | 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.