Pennsylvania County Map: All 67 Counties

Under the Pennsylvania County Code (Title 16 of the Pennsylvania Consolidated Statutes), counties are divided into nine population classes: First Class (Philadelphia), Second Class (Allegheny / Pittsburgh), Second Class A (Montgomery, Bucks, Delaware), Third through Eighth Class, and Cameron County in Eighth Class.

In non-charter counties governed by a three-member Board of County Commissioners, Section 501 of the County Code dictates a rare proportional voting requirement: each major political party nominates two candidates, but registered voters may cast ballots for only two choices in the general election.

This structural restriction mathematically ensures that the candidate from the minority political party who finishes in third place overall wins the third seat on the commission, institutionalizing bipartisanship in county tax assessments, prison boards, and elections boards.

Prior to 1854, the City of Philadelphia occupied just two square miles between the Delaware and Schuylkill rivers, surrounded by 28 independent boroughs, townships, and districts within Philadelphia County (including Northern Liberties, Kensington, and Spring Garden).

Rampant municipal fragmentation, gang warfare, and race and anti-Catholic nativist riots in the 1840s paralyzed local police. In response, the Pennsylvania General Assembly passed the Act of Consolidation of 1854, merging all municipalities within the county into a single unified City of Philadelphia.

Under the 1951 Philadelphia Home Rule Charter, municipal and county operations were formally consolidated. Today, the Philadelphia City Council and Mayor exercise all county legislative and executive powers, with the City Commissioners serving as the county board of elections.