231 is a North American telephone area code in the U.S. state of Michigan. It was created in June 1999 as a split from area code 616. 231 is essentially the northern half of the old 616 area code. 616 previously covered the entire western half of the state of Michigan, extending west from the north-south line aligned with the Mackinac Bridge.

The new 231's southern boundary closely follows the county lines between Muskegon County and Ottawa County and Kent County and Montcalm County.

Among the Michigan cities it serves are Big Rapids, Cadillac, Grant, Kalkaska, Ludington, Muskegon, Petoskey, and Traverse City.

[edit] External links

• Planning letter 167, which details 231's creation (PDF)
• Map of Michigan area codes at North American Numbering Plan Administration's website
• List of exchanges from AreaCodeDownload.com, 231 Area Code

State of Michigan area codes: 231, 248, 269, 313, 517, 586, 616, 734, 810, 906, 947, 989
	North: 906
West: Lake Michigan	area code 231	East: 989
	South: 616

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