NPA-NXX - 605-540

This is the 605-540 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. 605-540

The 605-540 subcode mainly covers North Sioux City in Union 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 Regular Landline registered to Level 3. 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 14399 comments across our systems for the 605-540 subcode.