Phone numbers in O'Fallon, Missouri
O'Fallon has 24 phone prefixes in area code 636.
Biggest holders: Brightspeed Of Missouri, AT&T Mobility, T-Mobile (including Sprint). This is the local calling area (rate center) where those prefixes were first assigned.
- Mobile carrier 33%
- Local phone company 33%
- Internet / business phone carrier 29%
- Phone company 4%
Every prefix in O'Fallon
Search the first six digits of a number in this list. If it's here, the number started in O'Fallon with the carrier shown. If it isn't, check the Missouri page or look the number up.
| Prefix | Carrier | Type | Assigned |
|---|---|---|---|
| 636-240 | Brightspeed Of Missouri | Local phone company | – |
| 636-272 | Brightspeed Of Missouri | Local phone company | – |
| 636-281 | Brightspeed Of Missouri | Local phone company | – |
| 636-293 | T-Mobile (including Sprint) | Mobile carrier | 2002 |
| 636-294 | Charter / Spectrum | Internet / business phone carrier | 2001 |
| 636-312 | AT&T Mobility | Mobile carrier | 2015 |
| 636-339 | T-Mobile (including Sprint) | Mobile carrier | 2020 |
| 636-351 | Boost / Virgin Mobile | Mobile carrier | 2022 |
| 636-379 | Brightspeed Of Missouri | Local phone company | – |
| 636-385 | Brightspeed Of Missouri | Local phone company | 2011 |
| 636-409 | Charter / Spectrum | Internet / business phone carrier | 2016 |
| 636-439 | AT&T Mobility | Mobile carrier | 2011 |
| 636-470 | Shelcomm | Phone company | 2026 |
| 636-474 | Brightspeed Of Missouri | Local phone company | – |
| 636-515 | AT&T Mobility | Mobile carrier | 2014 |
| 636-542 | Windstream (PAETEC) | Internet / business phone carrier | 2007 |
| 636-544 | AT&T Mobility | Mobile carrier | 2002 |
| 636-614 | Level 3 (Lumen) | Internet / business phone carrier | 2001 |
| 636-630 | Commio | Internet / business phone carrier | 2022 |
| 636-696 | Teleport Communications America | Internet / business phone carrier | – |
| 636-849 | T-Mobile (including Sprint) | Mobile carrier | 2017 |
| 636-874 | TON80 Communications | Internet / business phone carrier | 2022 |
| 636-978 | Brightspeed Of Missouri | Local phone company | – |
| 636-980 | Brightspeed Of Missouri | 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.