The township is on the northern side of Cumberland County and is bordered to the north by Perry County; the county line follows the ridgecrest of Blue Mountain, the northern edge of the Cumberland Valley. The eastern border is Lower Frankford Township, sister township caused by the 1921 split of old Frankford Township.Gardner Digital Library: Frankford Township. Accessed 23 Sep 2022. The twin townships' southern border with West Pennsboro Township was created in April of 1795 by the County Court and follows Conodoguinet Creek, a tributary of the Susquehanna River. Lower Mifflin Township is the western border of Upper Frankford Township. The township includes the unincorporated community of Bloserville.
