Area code 906 was assigned in an area code split of numbering plan area (NPA) 616 on March 19, 1961 in a flash cut, which means no permissive dialing period was implemented. 906 is among the least populous numbering plan areas in North America, serving only about 320,000 people. Therefore, the most recent NANPA projections do not list an exhaust date, explaining that the projected exhaust date is more than 30 years in the future. The area code has inspired an unofficial holiday in the Upper Peninsula on September 6 (906 correlating to the month/day date).
Area code 906 has telephone numbers assigned for the central office code 988. 988 has been designated nationwide as a dialing code for the National Suicide Prevention Lifeline, which creates a conflict for exchanges that permit seven-digit dialing. This area code is therefore scheduled to transition to ten-digit dialing, mandatory after October 24, 2021.
Area code 906 is used in the following cities:
- Iron Mountain
- St. Ignace
- Sault Ste. Marie
- Gmiter, Tanda (6 September 2016). "Happy #906 Day to da U.P., eh!". MLive. Retrieved 6 September 2017.
- "Transition to 10-digit dialing (for 988 as 3-digit access to National Suicide Prevention Hotline)" (PDF). North American Numbering Plan Administrator. January 8, 2021. Retrieved March 9, 2021.
- Map of Michigan area codes at North American Numbering Plan Administration's website
- List of exchanges from AreaCodeDownload.com, 906 Area Code
|North: 705/249, Lake Superior|
|West: 715/534||area code 906||East: 705/249, Lake Huron|
|South: 231, 715/534, 920, Lake Michigan|
|Ontario area codes: 226/519/548, 249/705, 289/365/905, 343/613, 416/437/647, 807|
|Wisconsin area codes: 262, 414, 534/715, 608, 920|