NPA-NXX - 605-400

This is the 605-400 subcode (NPA-NXX) prefix page. Follow a prefix to find the number you are looking for. We divide our pages up to make them more user friendly to navigate!

1. Area Codes
2. 605
3. 605-400

The 605-400 subcode mainly covers Sioux Falls in Minnehaha county. But other numbers maybe included as well.

We have a database of information derived from the public phone records of South Dakota state. Many of the numbers in this subcode are Cellular (Dedicated) registered to At&t Mobility. We hear they employ a large number of people in the South Dakota office.
Recently there have been an increase in reported calls, we've had over 169468 comments across our systems for the 605-400 subcode.