On February 19, 2018, the Pennsylvania Supreme Court imposed a new congressional district map that will take effect January 1, 2019. Current congressional districts remain the as they are today until the end of December, but the May primary and November general elections will be to select the candidates for the new congressional districts.
Marshall Township is currently in the 12th Congressional voting district. The current congressman is US Representative. Keith Rothfus. As of January 1, 2019, Marshall Township will be in the 17th Congressional voting district and for which you will be voting in the upcoming elections.
For further information, visit the Allegheny County Department of Elections website: http://www.alleghenycounty.us/elections/index.aspx