25 Pa. Stat. § 2706
In administering elections for the nomination and election of candidates for the United States House of Representatives and the General Assembly, county boards of election shall adhere to the following rule: Where an election district is used in or pursuant to a congressional redistricting statute or the Final Plan of the Legislative Reapportionment Commission to define the boundary of a congressional district or State legislative district, the boundary of such election district shall be the boundary existing and recognized by the Legislative Reapportionment Commission for the adoption of its Final Plan. The boundaries of the congressional districts, as established by statute, and State legislative districts as set forth in the Final Plan of the Legislative Reapportionment Commission shall remain in full force and effect for use thereafter until the next reapportionment or redistricting as required by law and shall not be deemed to be affected by any action taken pursuant to this article.
25 P.S. § 2706