40 C.F.R. § 81.55
The Northeast Pennsylvania-Upper Delaware Valley Interstate Air Quality Control Region (Pennsylvania-New Jersey) is redesignated to consist of the territorial area encompassed by the boundaries of the following jurisdictions or described area (including the territorial area of all municipalities (as defined in section 302(f) of the Clean Air Act, 42 U.S.C. 1857h(f) ) geographically located within the outermost boundaries of the area so delimited):
In the State of Pennsylvania: Berks County, Bradford County, Carbon County, Lackawanna County, Lehigh County, Luzerne County, Monroe County, Northampton County, Pike County, Schuylkill County, Sullivan County, Susquehanna County, Tioga County, Wayne County, Wyoming County.
In the State of New Jersey: Hunterdon County, Sussex County, Warren County.
40 C.F.R. §81.55