Area Code 406
Local Presence for Butte, Great Falls and Billings
You can increase your connection rate up to 30% by dialing from a local number.
Local Presence by Tenfold gives you one-click access from your existing phone system to a local number in the US area code 406 and more than 200 others.
Reach out to customers in Butte, Great Falls and Billings.
Source: Wikipedia