Area codes 717 and 223

Area codes 717 and 223 are telephone area codes in the North American Numbering Plan (NANP) for South Central Pennsylvania and the Susquehanna Valley. The numbering plan area (NPA) includes the Harrisburg, Lancaster and York metropolitan areas as well as most of the area generally known as Pennsylvania Dutch Country—an area of nearly two million people.

Pennsylvania (blue) with numbering plan area 717 shown in red.

Area code 717 was one of the original North American area codes established in 1947. It originally served the eastern half of the state except for the Delaware and Lehigh valleys, which were in area code 215. It stretched from the Maryland border to the south to the New York and New Jersey borders, making it the largest of Pennsylvania's original four plan areas and the second-largest east of the Mississippi River that did not cover an entire state, after Michigan's area code 616.

Despite the presence of five of the state's 15 largest cities (Harrisburg, Lancaster, York, Scranton and Wilkes-Barre), this part of Pennsylvania is not as densely populated as the Delaware and Lehigh Valleys. As a result, 717 remained unchanged for 41 years. For nearly all of this time, it was the largest numbering plan area on the Eastern Seaboard. It was pushed slightly eastward in 1994 as part of the split of Philadelphia's 215, when a few towns in eastern Lancaster County and western Chester County that were slated to transfer to area code 610 were instead shifted to 717. These areas were served by non-Bell companies who wanted to consolidate their eastern Pennsylvania subscriber base into a single area code.

By the mid-1990s, 717 was on the brink of exhaustion due to the proliferation of cell phones, pagers, and fax machines, particularly in Harrisburg, Lancaster, York, and Scranton/Wilkes-Barre. On 5 December 1998, the northern portion of the old 717 territory, centered on Scranton, Wilkes-Barre and Williamsport, received area code 570. As of May 2005, the subscriber number pool of 717 was allocated by 52%.

The Pennsylvania Utility Commission determined in 2010 that 717 would likely exhaust by the second quarter of 2018. Under consideration for relief were overlaying 717 with a second area code, or a split along an east-west boundary. An overlay would have required ten-digit dialing, though all customers with an existing 717 number would have been able to keep it. A split would have preserved seven-digit dialing. Most of those who testified in a public hearing supported an overlay as a cost-effective solution that would have spared customers the expense and burden of changing their numbers.[1] In October 2016, an overlay area code, 223, was approved, to become effective in 2017.[2] Since August 26, 2017, 10-digit dialing is mandatory.[3] Area code 223 became available for central office code assignments on September 25, 2017.[4]