You can find a map of Michigan with all of the area codes listed on AllAreaCodes.com. There are printable maps of every U.S. state with area codes available there.
Michigan has a total of 12 area codes, covering 11 regions. Covering Detroit and a few suburbs is the 313 area code. Covering Ann Arbor, the surrounding area and some Detroit suburbs is 734. Covering Macomb County, home to many Detroit suburbs, is 586. Oakland County is also home to many Detroit suburbs, such as Southfield and Birmingham, and is covered by two area codes: 248 and 947.
Lansing, the capital of Michigan, is in the 517 area code region. Kalamazoo and the rest of Southwest Michigan uses 269, 616 covers Grand Rapids and its suburbs and 810 covers Flint and Port Huron.
The northern part of the Lower Peninsula is covered by the 989 and 231 area codes. The Upper Peninsula uses 906.