Phone numbers in Castle Rock, Washington
Castle Rock has 3 phone prefixes in area codes 360, 564.
Biggest holders: CenturyLink / Lumen, Level 3 (Lumen), Terra Nova Telecom. 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 Castle Rock
Search the first six digits of a number in this list. If it's here, the number started in Castle Rock with the carrier shown. If it isn't, check the Washington page or look the number up.
| Prefix | Carrier | Type | Assigned |
|---|---|---|---|
| 360-274 | CenturyLink / Lumen | Local phone company | – |
| 360-967 | Level 3 (Lumen) | Internet / business phone carrier | 2005 |
| 564-777 | Terra Nova Telecom | Internet / business phone carrier | 2019 |
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.