Adams Formed: 22 Jan 1800 Parent: York	Allegheny Formed: 24 Sep 1788 Parent: Washington and Westmoreland	Armstrong Formed: 12 Mar 1800 Parent: Allegheny, Lycoming, and Westmoreland	Beaver Formed: 12 Mar 1800 Parent: Allegheny and Washington	Bedford Formed: 9 Mar 1771 Parent: Cumberland
Berks Formed: 11 Mar 1752 Parent: Chester, Lancaster, and Philadelphia	Blair Formed: 26 Feb 1846 Parent: Bedford and Huntingdon	Bradford Formed: 21 Feb 1810 Parent: Luzerne and Lycoming	Bucks Formed: 1682 Parent: Original County	Butler Formed: 12 Mar 1800 Parent: Allegheny
Cambria Formed: 26 Mar 1804 Parent: Bedford, Huntingdon, and Somerset	Cameron Formed: 29 Mar 1860 Parent: Clinton, Elk, McKean, and Potter	Carbon Formed: 13 Mar 1843 Parent: Monroe and Northampton	Centre Formed: 13 Feb 1800 Parent: Huntingdon, Lycoming, Mifflin, and Northumberland	Chester Formed: 1682 Parent: Original County
Clarion Formed: 11 Mar 1839 Parent: Armstrong and Venango	Clearfield Formed: 26 Mar 1804 Parent: Huntingdon and Lycoming	Clinton Formed: 21 Jun 1839 Parent: Centre and Lycoming	Columbia Formed: 22 Mar 1813 Parent: Northumberland	Crawford Formed: 12 Mar 1800 Parent: Allegheny
Cumberland Formed: 27 Jan 1750 Parent: Lancaster	Dauphin Formed: 4 Mar 1785 Parent: Lancaster	Delaware Formed: 26 Sep 1789 Parent: Chester	Elk Formed: 18 Apr 1843 Parent: Clearfield, Jefferson, and McKean	Erie Formed: 12 Mar 1800 Parent: Allegheny and Crawford
Fayette Formed: 26 Sep 1783 Parent: Westmoreland	Forest Formed: 11 Apr 1848 Parent: Jefferson and Venango	Franklin Formed: 9 Sep 1784 Parent: Cumberland	Fulton Formed: 19 Apr 1850 Parent: Bedford	Greene Formed: 9 Feb 1796 Parent: Washington
Huntingdon Formed: 20 Sep 1787 Parent: Bedford	Indiana Formed: 30 Mar 1803 Parent: Lycoming and Westmoreland	Jefferson Formed: 26 Mar 1804 Parent: Lycoming	Juniata Formed: 2 Mar 1831 Parent: Mifflin	Lackawanna Formed: 13 Aug 1878 Parent: Luzerne
Lancaster Formed: 10 May 1729 Parent: Chester	Lawrence Formed: 20 Mar 1849 Parent: Beaver and Mercer	Lebanon Formed: 16 Feb 1813 Parent: Dauphin and Lancaster	Lehigh Formed: 6 Mar 1812 Parent: Northampton	Luzerne Formed: 25 Sep 1786 Parent: Northumberland
Lycoming Formed: 13 Apr 1795 Parent: Northumberland	McKean Formed: 26 Mar 1804 Parent: Lycoming	Mercer Formed: 12 Mar 1800 Parent: Allegheny and Crawford	Mifflin Formed: 19 Sep 1789 Parent: Cumberland and Northumberland	Monroe Formed: 1 Apr 1836 Parent: Northampton and Pike
Montgomery Formed: 10 Sep 1784 Parent: Philadelphia	Montour Formed: 3 May 1850 Parent: Columbia	Northampton Formed: 11 Mar 1752 Parent: Bucks	Northumberland Formed: 21 Mar 1772 Parent: Bedford, Berks, Cumberland, Lancaster, and Northampton	Perry Formed: 22 Mar 1820 Parent: Cumberland
Philadelphia Formed: 1682 Parent: Original County	Pike Formed: 26 Mar 1814 Parent: Wayne	Potter Formed: 26 Mar 1804 Parent: Lycoming	Schuylkill Formed: 1 Mar 1811 Parent: Berks and Northampton	Snyder Formed: 2 Mar 1855 Parent: Union
Somerset Formed: 17 Apr 1795 Parent: Bedford	Sullivan Formed: 15 Mar 1847 Parent: Lycoming	Susquehanna Formed: 21 Feb 1810 Parent: Luzerne	Tioga Formed: 26 Mar 1804 Parent: Lycoming	Union Formed: 22 Mar 1813 Parent: Northumberland
Venango Formed: 12 Mar 1800 Parent: Allegheny, Crawford, and Lycoming	Warren Formed: 12 Mar 1800 Parent: Allegheny, Crawford, Lycoming, and Venango	Washington Formed: 28 Mar 1781 Parent: Westmoreland	Wayne Formed: 21 Mar 1798 Parent: Northampton	Westmoreland Formed: 26 Feb 1773 Parent: Bedford

Wyoming Formed: 4 Apr 1842 Parent: Luzerne	York Formed: 19 Aug 1749 Parent: Lancaster