what area code 412
Summary. Until 1997, Pennsylvania had four area codes â 814, 412, 717 and 215. With the increased use of cell phones and consumers purchasing additional lines in their homes, the demand for additional telephone lines exploded.17 region-The 717 area codes stretches from Lancaster to Harrisburg, to York and Fulton County. Western Pennsylvania. 412, 724 and 878 region-The 412 area code is primarily located in Pittsburgh and 724 covers the suburbs of Pittsburgh.