Phone numbers in Washington, Missouri
Washington has 13 phone prefixes in area code 636.
Biggest holders: AT&T (local phone), Onvoy, Windstream (PAETEC). This is the local calling area (rate center) where those prefixes were first assigned.
- Mobile carrier 23%
- Local phone company 31%
- Internet / business phone carrier 38%
- Phone company 8%
Every prefix in Washington
Search the first six digits of a number in this list. If it's here, the number started in Washington with the carrier shown. If it isn't, check the Missouri page or look the number up.
| Prefix | Carrier | Type | Assigned |
|---|---|---|---|
| 636-221 | AT&T (local phone) | Local phone company | 2002 |
| 636-231 | Windstream (PAETEC) | Internet / business phone carrier | – |
| 636-239 | AT&T (local phone) | Local phone company | – |
| 636-241 | Verizon Wireless | Mobile carrier | 2022 |
| 636-266 | Level 3 (Lumen) | Internet / business phone carrier | 2002 |
| 636-283 | Teleport Communications America | Internet / business phone carrier | 2007 |
| 636-291 | AT&T Mobility | Mobile carrier | 2025 |
| 636-369 | Onvoy | Internet / business phone carrier | 2021 |
| 636-390 | AT&T (local phone) | Local phone company | – |
| 636-392 | Aurora Communications | Phone company | 2008 |
| 636-432 | AT&T (local phone) | Local phone company | 2006 |
| 636-667 | T-Mobile (including Sprint) | Mobile carrier | 2002 |
| 636-900 | Onvoy | Internet / business phone carrier | 2015 |
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.