The 26th Senate District includes Chester and Delaware Counties.

Part of Chester County consisting of the Townships of Easttown and Willistown and Part of Delaware County consisting of the Townships of Marple, Newtown, Ridley, Springfield, Tinicum, Upper Darby and Upper Providence and the Boroughs of Aldan, Clifton Heights, East Lansdowne, Glenolden, Media, Millbourne, Morton, Prospect Park, Ridley Park, Rutledge and Swarthmore.