Area code 878 is an overlay for both 412 and 724 in southwestern Pennsylvania, including Pittsburgh and surrounding areas. Introduced in 2001, it spans both the urban and suburban areas of a region known for its industrial heritage, sports culture, and growing tech scene. Pittsburgh’s transformation from a steel town to a hub of healthcare and education has driven demand for additional phone numbers, making ten-digit dialing necessary. Area code 878 is emblematic of this ongoing growth, complementing the legacy of 412 while extending into the broader Pittsburgh metro and surrounding counties.