Pennsylvania · Eastern Time
878 Area Code
Area code 878 is in Pennsylvania, serving Pittsburgh and southwestern Pennsylvania, overlaying both 412 and 724. It is in the Eastern Time zone. It shares its territory with overlay codes 412 and 724, so 10-digit dialing is required.
Last updated October 1, 2026 · Source: NANPA
Where is the 878 area code?
878 is a Pennsylvania area code covering Pittsburgh and southwestern Pennsylvania, overlaying both 412 and 724. In the wider directory it sits in the Northeast region.
Cities in the 878 area code
- Pittsburgh
- Penn Hills
- Mount Lebanon
- Bethel Park
- Monroeville
- McKeesport
- West Mifflin
- Upper St. Clair
- Baldwin
- Shaler
- McCandless
- New Castle
- Washington
- Greensburg
Counties served by 878
Allegheny County.
878 overlay codes and dialing
The 878 territory is covered by an overlay of 3 area codes: 412, 724, 878. All of them serve the same geographic area, and the original code is 412. Because more than one code covers the same ground, 10-digit dialing is mandatory — you must dial the area code for every local call. New phone lines may be assigned any of these codes.
History of the 878 area code
878 went into service on August 17, 2001 as an overlay of 412, relieving number exhaustion in the Pittsburgh area. Rather than splitting the region, the overlay lets existing customers keep their numbers while new lines draw from the added code. Learn more in our overlay guide.
Is 878 a scam or spam risk?
878 is a legitimate geographic area code, not a premium or toll line, so a call from it costs you nothing extra. That said, scammers frequently spoof real local area codes to look familiar on caller ID. A genuine 878 number on your screen is no guarantee the caller is in Pittsburgh, PA or trustworthy. See spam & scam-risk area codes for how spoofing works and how to respond.
Other Pennsylvania area codes
Explore more
See every code in Pennsylvania, compare codes across the Northeast region, or view all Eastern Time codes. You can also browse the 8XX block or the complete numeric list of US area codes.
New to how this all works? Start with how area codes work, then read up on overlays, 10-digit dialing, and spam & scam-risk codes. To check another number, use the area code lookup tool.
Quick answers
878 area code FAQ
Where is the 878 area code?
The 878 area code is in Pennsylvania, covering Pittsburgh and southwestern Pennsylvania, overlaying both 412 and 724, in the Northeast region.
What cities are in the 878 area code?
Cities in the 878 area code include Pittsburgh, Penn Hills, Mount Lebanon, Bethel Park, Monroeville, McKeesport, West Mifflin, Upper St. Clair, Baldwin and Shaler.
What time zone is 878 in?
878 is in the Eastern Time zone.
What is the overlay for the 878 area code?
878 shares its territory with 412 and 724. All 3 codes (412, 724, 878) serve the same area, so 10-digit dialing is required for every call.
When did the 878 area code start?
878 went into service on August 17, 2001 as an overlay of 412.
Do I have to dial 10 digits for 878?
Yes. Because 878 is an overlay area, you must dial the full 10-digit number (area code + 7 digits) for every call.
Is 878 a toll-free or premium code?
No. 878 is a standard geographic area code, so calling it costs the same as any local or long-distance call on your plan. Toll-free calls use 800, 888, 877, 866, 855, 844 or 833.