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Michigan: Western (231, 269, 616, 906) Central (517, 989) Eastern (248, 313, 586, 734, 810, 947)
Eastern MichiganArea Code 313 originally covered all of eastern lower Michigan near Detroit. This area is entirely in the Detroit LATA.
Area Code 810
The northern portion of eastern Michigan was split from 313 to become the 810 area code on December 1st, 1993. Permissive dialing ended August 10th, 1994.
Area Code 248
Oakland County Michigan was split from 810 to become the 248 area code on May 10th, 1997. Permissive dialing ended September 13th, 1997.
Area Code 586
In September 1999 the industry decided to further relieve 810 by overlaying the 586 area code, effective May 6th, 2000. On March 10th, 2000, that plan was withdrawn. On December 11th, 2000, the Michigan Public Service Commission approved a split of 810 effective September 22nd, 2001. Permissive dialing ended March 23rd, 2002. The commission initially allowed wireless phones in the eleven rate centers changing to 586 to remain in 810. On April 17th, 2001, the commission recinded the permanent grandfathering and set a permissive end date for wireless of March 22nd, 2003.
Area Code 947
On April 17th, 2001, the Michigan Public Service Commission approved an overlay of area code 248 with area code 947. Permissive 10 digit dialing began January 26th, 2002, and was scheduled to end (requiring 10 digit dialing of all local calls) on June 8th, 2002. On March 21st, 2002, the MPSC extended permissive to September 7th, 2002.
Area Code 313
Area Code 313 was one of the original 86 area codes assigned in 1947. The first split in 1993 (see above) created the 810 area code.
Area Code 734
Exchanges outside of Detroit were split from 313 to become the 734 area code on December 13th, 1997. Permissive dialing ended July 25th, 1998.
In February of 2000 a plan was announced to overlay 313 with area code 679 and overlay 734 with area code 278. The plan was suspended in April of 2000 and has not resumed. (The plan to overlay 248 was also suspended at that time but has now been completed.)