NPA-NXX - 406-433

This is the 406-433 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. 406
3. 406-433

The 406-433 subcode mainly covers Sidney in Richland county. But other numbers maybe included as well.

We have a database of information derived from the public phone records of Montana state. Many of the numbers in this subcode are Regular Landline registered to Mid-rivers Telephone Cooperative. We hear they employ a large number of people in the Montana office.
Recently there have been an increase in reported calls, we've had over 9746 comments across our systems for the 406-433 subcode.