16 Pa. Stat. § 5224
From and after the time when a zoning commission of the county, in accordance with the procedure herein specified, makes, adopts and certifies to the county commissioners each zoning plan, including both the full text of a zoning ordinance and the maps, then the county commissioners may, by ordinance, exercise the powers hereinbefore granted to it in this subdivision, and for the purpose of such exercise, the county commissioners may divide the territory of the county which lies outside of municipalities which now have and enforce zoning ordinances into districts or zones of such number, shape or area as it may determine. Within such districts or any of them, they may regulate the erection, construction, reconstruction, alteration and uses of buildings and structures and the uses of land, and may require and provide for the issuance of building permits as a condition precedent to the right to erect, construct, reconstruct or alter any building or structure within any district covered by such zoning ordinance. All such regulations shall be uniform for each class or kind of buildings throughout any district, but the regulations in one district may differ from those in other districts.
16 P.S. § 5224