North American area code in use in Michigan. It went into service on December 1, 1993, split off from the existing 313 area code; 313 went to Detroit and surrounding counties, while 810 went to the remainder of the lower peninsula previously covered by 313.
From August 1962 to the end of 1981, 810 was used for TWX/WADS service in the midwestern and southern U.S.
Reference:
AreaCode-Info.com. "Area Code History." http://areacode-info.com/ History of Area Codes (4 Jun. 2001).