68 Pa. Stat. § 951
The system of plane rectangular coordinates which has been established and adopted by the National Ocean Service/National Geodetic Survey (formerly the United States Coast and Geodetic Survey) or its successors for defining and stating the positions or locations of points on the surface of the earth within the Commonwealth of Pennsylvania is hereafter known and designated as the "Pennsylvania Coordinate System."
For the purpose of the use of this system, the Commonwealth is divided into two zones: the "North Zone," and the "South Zone."
The area now included in the following counties shall constitute the North Zone:
Bradford, Cameron, Carbon, Centre, Clarion, Clearfield, Clinton, Columbia, Crawford, Elk, Erie, Forest, Jefferson, Lackawanna, Luzerne, Lycoming, McKean, Mercer, Monroe, Montour, Northumberland, Pike, Potter, Sullivan, Susquehanna, Tioga, Union, Venango, Warren, Wayne, and Wyoming.
The area now included in the following counties shall constitute the South Zone:
Adams, Allegheny, Armstrong, Beaver, Bedford, Berks, Blair, Bucks, Butler, Cambria, Chester, Cumberland, Dauphin, Delaware, Fayette, Franklin, Fulton, Greene, Huntingdon, Indiana, Juniata, Lancaster, Lawrence, Lebanon, Lehigh, Mifflin, Montgomery, Northampton, Perry, Philadelphia, Schuylkill, Snyder, Somerset, Washington, Westmoreland, and York.
68 P.S. § 951