Area code 612 is part of the North American Numbering Plan (NANP) of the public switched telephone network for the city of Minneapolis, Minnesota and a few surrounding areas such as Fort Snelling, St. Anthony and Richfield. By geographical area, it is the smallest area code in the state of Minnesota. However, like every single metropolitan area code in the United States, the region used to be much larger, accounting for the entire Twin Cities region and a wide area surrounding it. The Twin Cities metro calling area (612, most of area codes 651, 952, and 763, plus parts of area codes 320 and 507 in addition to 612) is the largest geographic toll-free calling zone in the United States.