Area Code 412 History:
Area code 412 was put into service. In 1988 area code 412 was split to form area code 724. In 2001 area code 412 was overlaid with area code 878.
Counties in Pennsylvania within area code 412 include:
Allegheny County and Westmoreland County.
Major cities or places in Pennsylvania within area code 412 include:
Area codes 412 and 878 serve the Pittsburgh metropolitian area including the larger cities and communities of Bethel Park, Mccandless Township, Mckeesport, Mount Lebanon, Municipality Of Monroeville, Penn Hills, Pittsburgh, Plum, Ross Township, Shaler Township, Upper St. Clair, and West Mifflin in addition to many smaller communities.