Legislative districts in Mercer and Lawrence counties will change shape under the final reapportionment plan set up by the state legislature to align districts with population shifts next year.
7th House District
Losing: Delaware Township, Mercer County.
Gaining: East Lackawannock Township, Mercer County.
8th House District
Losing: Venango, Allegheny, Washington and Parker townships in Venango County.
Gaining: Springfield Township in Mercer County and Worth, Brady, Clay, Concord, Fairview, Franklin, Center, Muddy Creek, Lancaster and Jackson townships as well as the boroughs of Portersville and Zelienople in Butler County.
9th House District
Losing: New Beaver and South New Castle boroughs, Lawrence County.
Gaining: Pulaski Township, Lawrence County; Darlington Township, Darlington Borough and a portion of South Beaver Township, Beaver County.
10th House District
Losing: Pulaski, Volant, Wilmington and Washington townships and New Wilmington Borough in Lawrence County; 13 townships and boroughs in Butler County.
Gaining: South New Castle Borough and portions of North Beaver and New Beaver townships, Lawrence County; Slippery Rock Township and Slippery Rock Borough in Butler; six communities in Beaver County.
17th House District
Losing: East Lackawannock and Springfield townships in Mercer County.
Gaining: North Shenango Township in Crawford County and the boroughs of New Wilmington and Volant as well as Wilmington and Washington townships in Lawrence County.
47th Senate District
Gaining: Shenango Township, Lawrence County; three communities in Beaver County and one portion of one in Allegheny County.
50th Senate District
Losing: Nine townships in Erie County.
Gaining: Lancaster and Worth townships in Butler County and Neshannock, Hickory, Perry, Plain Grove, Scott, Slippery Rock, Washington and Wilmington townships and the boroughs of New Wilmington and Volant in Lawrence County.