the roadway opened between plymouth meeting and the lehigh valley interchange near allentown on november 23, 1955. the highway was extended north to emerald on december 28, 1955. the northeast extension was opened between emerald and wyoming valley on april 1, 1957. the entire length of the northeast extension was finished on november 7, 1957 with the completion of the northernmost part between wyoming valley and scranton. the part of the northeast extension between scranton and the new york border would not be built as part of the pennsylvania turnpike system but rather the interstate highway system as i-81. at the northern terminus, the northeast extension narrowed to two lanes along the northbound off-ramp at scranton to come to its northern terminus, with an abandoned short spur of the mainline heading north. a pair of trumpet interchanges were built to connect the northeast extension and i-81. in 1980, the roadway would be designated pa 9.