The eastern border of the district runs from the northern most corner of Jefferson County, NY on the St. Lawrence River, south into the state of Pennsylvania. The boundary then continues south along the eastern border of Susquehanna County, PA and then heads west, along the southern borders of Susquehanna, Bradford, Sullivan, and Tioga Counties to U.S. Route 15. The district boundary then follows U.S. Route 15 south to the Pennsylvania-Maryland state line, at which point it turns to follow the Pennsylvania state line to the southwestern corner of the state. The district boundary then turns north, following the state border with Ohio to Lake Erie, following along Lake Erie to the New York state line. The boundary then follows the NY State border south and east to the western border of McKean County, where it runs south along the western border of McKean County, and then east along the southern borders of McKean and Potter Counties. The district boundary then follows the western border of Tioga County to the New York state line, extending north to the Rochester area and Lake Ontario, which also serves as a natural, northern boundary.