Phone numbers in Castlewood, South Dakota
Castlewood has 3 phone prefixes in area code 605.
Biggest holders: Mcc Telephony Of The Mid-west, Interstate Telecom Coop, Verizon Wireless. This is the local calling area (rate center) where those prefixes were first assigned.
- Mobile carrier 33%
- Internet / business phone carrier 33%
- Phone company 33%
Every prefix in Castlewood
Search the first six digits of a number in this list. If it's here, the number started in Castlewood with the carrier shown. If it isn't, check the South Dakota page or look the number up.
| Prefix | Carrier | Type | Assigned |
|---|---|---|---|
| 605-414 | Mcc Telephony Of The Mid-west | Internet / business phone carrier | 2010 |
| 605-793 | Interstate Telecom Coop | Phone company | – |
| 605-804 | Verizon Wireless | Mobile carrier | 2017 |
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.