Senator Pileggi and Senator Costa Announce Online Access to Historic Senate Maps

For Immediate Release

HARRISBURG – Maps of state Senate districts dating back to 1790, when the Senate of Pennsylvania was first established, are now available online.

Senate Majority Leader Dominic Pileggi (R-9) and Senate Democratic Leader Jay Costa (D-43) announced today that PDF versions of the maps have been posted to Pennsylvania’s redistricting website,, along with the associated shapefiles. Interactive maps will be available in the coming weeks.

“These maps are a window into our past,” Senator Pileggi said. “Knowing this history can provide a deeper understanding of the issues confronted by previous General Assemblies through the decades. This is a tremendous resource, and I’m pleased it will be freely available for anyone interested in studying the history of the Senate.”

“The Internet provides a platform where we can give the citizens of Pennsylvania greater access to state government,” said Senator Costa. “This historical perspective will be an important resource. People will be able to see Pennsylvania’s evolution from our very first legislative districts in 1790 to today.”

The 18 newly-posted historic Senate maps feature current county lines, putting prior districts in a modern context. When Senate districts were first created in 1790, Pennsylvania had just 21 counties – fewer than a third of the 67 that exist today. Pennsylvania’s final county, Lackawanna, was established in 1878.

Many changes in Senate districts have taken place over the 223 years that the chamber has existed. The first Senate included 12 districts and 18 senators – two districts were represented by three Senators each, and two other districts were represented by two Senators each. Such “multi-member” districts were used until 1874, when the state was apportioned into 50 Senate districts, the same number in use today.

Although population shifts within Pennsylvania have necessitated many changes in Senate districts through the decades, some of the outlines in the 1874 map are not altogether different from the current lines. Senate District 43, for example, was and is based in the City of Pittsburgh, while Senate District 9 was and is based in Delaware County.

The maps posted today reflect Senate districts as they existed in 1790, 1794, 1801, 1808, 1815, 1822, 1829, 1836, 1843, 1850, 1857, 1864, 1871, 1874, 1906, 1921, 1937 (a plan later rejected by the state Supreme Court), and 1964. Maps reflecting the districts of 1966 (a plan drawn by the state Supreme Court), 1971, 1981, 1991, and 2001 were posted earlier, along with the plans approved by the current Legislative Reapportionment Commission in 2011 and 2012.


Erik Arneson (Senator Pileggi), 717-787-4712
Stacey Witalec (Senator Costa), 717-787-7683