Phone numbers in Chelsea, Michigan
Chelsea has 9 phone prefixes in area code 734.
Biggest holders: AT&T (local phone), Onvoy, Windstream (PAETEC). This is the local calling area (rate center) where those prefixes were first assigned.
- Local phone company 22%
- Internet / business phone carrier 78%
Every prefix in Chelsea
Search the first six digits of a number in this list. If it's here, the number started in Chelsea with the carrier shown. If it isn't, check the Michigan page or look the number up.
| Prefix | Carrier | Type | Assigned |
|---|---|---|---|
| 734-385 | Windstream (PAETEC) | Internet / business phone carrier | – |
| 734-433 | AT&T (local phone) | Local phone company | – |
| 734-475 | AT&T (local phone) | Local phone company | – |
| 734-488 | Onvoy | Internet / business phone carrier | 2020 |
| 734-562 | Comcast | Internet / business phone carrier | – |
| 734-570 | Onvoy | Internet / business phone carrier | 2023 |
| 734-593 | Teleport Communications America | Internet / business phone carrier | – |
| 734-627 | MCImetro (Verizon Business) | Internet / business phone carrier | – |
| 734-719 | Level 3 (Lumen) | Internet / business phone carrier | 2001 |
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.