Area code 724

History

In 1947, area code 412 was assigned as one of 86 original North American area codes to a numbering plan area that comprised the entire southwestern corner of Pennsylvania.

The regional carrier Bell Atlantic wanted to implement area code 724 as an overlay complex with 412 at a time when overlays were still a new concept, and were met with resistance because of the requirement for ten-digit dialing. As a result, 724 was implemented by assigning nearly all of the 412 territory outside Allegheny County with the new area code. This created an area code enclave in the city of Pittsburgh.

Within only two years, both 724 and 412 were nearing exhaustion due to rapid growth of telecommunication services in the Pittsburgh area from proliferation of cell phones and pagers. By this time, overlays had gained more acceptance, and area code 878 was implemented as an overlay complex with both the 412 and 724 territories on August 17, 2001, after rationing of central office prefixes ended. Since that date, ten-digit dialing has been mandatory in southwestern Pennsylvania.

Telephone number conserving practices mitigated exhaustion of area codes 724 and 412 until April, 2013. The first 878 numbers were issued in April 2013, after 724 central office codes were exhausted. The first 878 numbers in the 412 territory were issued a few years later.