List of United States senators from Pennsylvania

Pennsylvania ratified the United States Constitution on December 12, 1787, and elects its U.S. senators to class 1 and class 3. Officeholders are popularly elected, for a six-year term, beginning January 3. Elections are held the first Tuesday after November 1. Before 1914, they were chosen by the Pennsylvania General Assembly; before 1935, their terms began March 4. The state's current U.S. senators are Democrats Bob Casey Jr. (since 2007) and John Fetterman (since 2023). Arlen Specter was Pennsylvania's longest-serving senator (1981–2011).

Current delegation

Bob Casey Jr. (D)

John Fetterman (D)

List of senators

#	Senator	Party	Dates in office	Electoral history	T	C	T	Electoral history	Dates in office	Party	Senator	#
Class 1 Class 1 U.S. senators belong to the electoral cycle that has recently been contested in 2000, 2006, 2012, and 2018. The next election will be in 2024.						C	Class 3 Class 3 U.S. senators belong to the electoral cycle that has recently been contested in 2004, 2010, 2016, and 2022. The next election will be in 2028.
1	William Maclay	Anti- Admin.	Mar 4, 1789 – Mar 3, 1791	Elected in 1788. Lost re-election.	1	1st	1	Elected in 1788. Retired.	Mar 4, 1789 – Mar 3, 1795	Pro- Admin.	Robert Morris	1
Vacant			Mar 4, 1791 – Dec 1, 1793	Legislature failed to elect.	2	2nd
2	Albert Gallatin	Anti- Admin.	Dec 2, 1793 – Feb 28, 1794	Elected to finish the vacant term. Election voided.		2nd
2	Albert Gallatin	Anti- Admin.	Dec 2, 1793 – Feb 28, 1794	Elected to finish the vacant term. Election voided.		3rd
Vacant			Mar 1, 1794 – Apr 23, 1794
3	James Ross	Pro- Admin.	Apr 24, 1794 – Mar 3, 1803	Elected to finish the vacant term that happened from 1791 to 1793.
		Federalist				4th	2	Elected in 1795. Retired.	Mar 4, 1795 – Mar 3, 1801	Federalist	William Bingham	2
				Re-elected in 1797. Retired.	3	5th
						6th
						7th	3	Elected in 1801. Resigned to become Supervisor of Revenue of Pennsylvania.	Mar 4, 1801 – Jun 30, 1801	Democratic- Republican	Peter Muhlenberg	3
									Jun 30, 1801 – Dec 17, 1801	Vacant
								Elected to finish Muhlenberg's term. Retired.	Dec 17, 1801 – Mar 3, 1807	Democratic- Republican	George Logan	4
4	Samuel Maclay	Democratic- Republican	Mar 4, 1803 – Jan 4, 1809	Elected in 1802. Resigned.	4	8th
						9th
						10th	4	Elected in 1806. Retired.	Mar 4, 1807 – Mar 3, 1813	Democratic- Republican	Andrew Gregg	5
Vacant			Jan 4, 1809 – Jan 9, 1809	Vacant
5	Michael Leib	Democratic- Republican	Jan 9, 1809 – Feb 14, 1814	Elected in 1809 to finish Maclay's term, having been elected to the next term.^[1]
				Elected in 1808.^[2] Resigned to become Postmaster of Philadelphia.	5	11th
						12th
						13th	5	Elected in 1812.^[3] Retired.	Mar 4, 1813 – Mar 3, 1819	Democratic- Republican	Abner Lacock	6
Vacant			Feb 14, 1814 – Feb 24, 1814
6	Jonathan Roberts	Democratic- Republican	Feb 24, 1814 – Mar 3, 1821	Elected to finish Leib's term.
				Re-elected in late 1814.	6	14th
						15th
						16th	6	Elected in 1818. Retired.	Mar 4, 1819 – Mar 3, 1825	Democratic- Republican	Walter Lowrie	7
Vacant			Mar 4, 1821 – Dec 10, 1821	Legislature failed to elect.	7	17th
7	William Findlay	Democratic- Republican	Dec 10, 1821 – Mar 3, 1827	Elected late in 1821. Retired.		17th
		Democratic- Republican				18th
		Jacksonian				19th	7	Elected in 1825. Lost re-election.	Mar 4, 1825 – Mar 3, 1831	National Republican	William Marks	8
8	Isaac D. Barnard	Jacksonian	Mar 4, 1827 – Dec 6, 1831	Elected in 1826. Resigned to due ill health.	8	20th
						21st
						22nd	8	Elected in 1830. Resigned to become U.S. Minister to Russia.	Mar 4, 1831 – Jun 30, 1834	Jacksonian	William Wilkins	9
Vacant			Dec 6, 1831 – Dec 13, 1831
9	George M. Dallas	Jacksonian	Dec 13, 1831 – Mar 3, 1833	Elected to finish Barnard's term. Retired.
Vacant			Mar 4, 1833 – Dec 7, 1833	Legislature failed to elect.	9	23rd
10	Samuel McKean	Jacksonian	Dec 7, 1833 – Mar 3, 1839	Elected late in 1833.
									Jun 30, 1834 – Dec 6, 1834	Vacant
								Elected to finish Wilkins's term.	Dec 6, 1834 – Mar 5, 1845	Jacksonian	James Buchanan	10
						24th		Elected to finish Wilkins's term.		Jacksonian
		Democratic				25th	9	Re-elected in 1836.		Democratic
Vacant			Mar 4, 1839 – Jan 14, 1840	Legislature failed to elect.	10	26th
11	Daniel Sturgeon	Democratic	Jan 14, 1840 – Mar 3, 1851	Elected late in 1840.		26th
						27th
						28th	10	Re-elected in 1843. Resigned to become U.S. Secretary of State.
				Re-elected in 1845. Retired.	11	29th
									Mar 5, 1845 – Mar 13, 1845	Vacant
								Elected in 1845 to finish Buchanan's term. Retired.	Mar 13, 1845 – Mar 3, 1849	Democratic	Simon Cameron	11
						30th		Elected in 1845 to finish Buchanan's term. Retired.	Mar 13, 1845 – Mar 3, 1849	Democratic	Simon Cameron	11
						31st	11	Elected in 1849.	Mar 4, 1849 – Mar 3, 1855	Whig	James Cooper	12
12	Richard Brodhead	Democratic	Mar 4, 1851 – Mar 3, 1857	Elected in 1851.	12	32nd
						33rd
						34th	12	Legislature failed to elect.	Mar 4, 1855 – Jan 14, 1856	Vacant
						34th		Elected late in 1856. Retired.	Jan 14, 1856 – Mar 3, 1861	Democratic	William Bigler	13
13	Simon Cameron	Republican	Mar 4, 1857 – Mar 4, 1861	Elected in 1857. Resigned to become U.S. Secretary of War.	13	35th
13	Simon Cameron	Republican	Mar 4, 1857 – Mar 4, 1861	Elected in 1857. Resigned to become U.S. Secretary of War.		36th
Vacant			Mar 4, 1861 – Mar 14, 1861			37th	13	Elected in 1861. Lost re-election.	Mar 4, 1861 – Mar 3, 1867	Republican	Edgar Cowan	14
14	David Wilmot	Republican	Mar 14, 1861 – Mar 3, 1863	Elected in 1861 to finish Cameron's term. Retired.		37th
15	Charles R. Buckalew	Democratic	Mar 4, 1863 – Mar 3, 1869	Elected in 1863.	14	38th
						39th
						40th	14	Elected in 1867.	Mar 4, 1867 – Mar 12, 1877	Republican	Simon Cameron	15
16	John Scott	Republican	Mar 4, 1869 – Mar 3, 1875	Elected in 1869. Retired.	15	41st
						42nd
						43rd	15	Re-elected in 1873. Resigned.
17	William A. Wallace	Democratic	Mar 4, 1875 – Mar 3, 1881	Elected in 1875. Lost re-election.	16	44th
						45th
									Mar 12, 1877 – Mar 20, 1877	Vacant
								Elected in 1877 to finish his father's term.	Mar 20, 1877 – Mar 3, 1897	Republican	J. Donald Cameron	16
						46th	16	Re-elected in 1879.
18	John I. Mitchell	Republican	Mar 4, 1881 – Mar 3, 1887	Elected in 1881.	17	47th
						48th
						49th	17	Re-elected in 1885.
19	Matthew Quay	Republican	Mar 4, 1887 – Mar 3, 1899	Elected in early 1887.	18	50th
						51st
						52nd	18	Re-elected in 1891. Retired.
				Re-elected in 1893. Legislature failed to re-elect.	19	53rd
						54th
						55th	19	Elected in 1897.	Mar 4, 1897 – Dec 31, 1921	Republican	Boies Penrose	17
	Vacant		Mar 4, 1899 – Jan 16, 1901	Quay was appointed to continue the term, but the Senate rejected his appointment.	20	56th
	Matthew Quay	Republican	Jan 16, 1901 – May 28, 1904	Elected late in 1901. Died.		56th
						57th
						58th	20	Re-elected in 1903.
20	Philander C. Knox	Republican	Jun 10, 1904 – Mar 3, 1909	Appointed to continue Quay's term. Elected in 1905 to finish Quay's term.^[4]		58th
				Re-elected in 1905.^[5] Resigned to become U.S. Secretary of State.	21	59th
						60th
Vacant			Mar 4, 1909 – Mar 17, 1909			61st	21	Re-elected in 1909.
21	George T. Oliver	Republican	Mar 17, 1909 – Mar 3, 1917	Elected to finish Knox's term		61st
				Re-elected in 1911. Retired.	22	62nd
						63rd
						64th	22	Re-elected in 1914.
22	Philander C. Knox	Republican	Mar 4, 1917 – Oct 12, 1921	Elected in 1916. Died.	23	65th
						66th
						67th	23	Re-elected in 1920. Died.
Vacant			Oct 12, 1921 – Oct 24, 1921
23	William E. Crow	Republican	Oct 24, 1921 – Aug 2, 1922	Appointed to continue Knox's term. Died.
									Dec 31, 1921 – Jan 9, 1922	Vacant
								Appointed to continue Penrose's term. Elected to finish Penrose's term. Lost renomination.	Jan 9, 1922 – Mar 3, 1927	Republican	George W. Pepper	18
Vacant			Aug 2, 1922 – Aug 8, 1922
24	David A. Reed	Republican	Aug 8, 1922 – Jan 3, 1935	Appointed to continue Knox's term. Elected to finish Knox's term.
				Elected in 1922.	24	68th
						69th
						70th	24	William Scott Vare (R) was elected in 1926, but the Governor refused to certify the election and the Senate refused to qualify him.	Mar 4, 1927 – Dec 9, 1929	Vacant
				Re-elected in 1928. Lost re-election.	25	71st			Mar 4, 1927 – Dec 9, 1929	Vacant
								Appointed to continue Vare's term. Lost nomination to finish Vare's term.	Dec 11, 1929 – Dec 1, 1930	Republican	Joseph R. Grundy	19
								Elected in 1930 to finish Vare's term	Dec 2, 1930 – Jan 3, 1945	Republican	James J. Davis	20
						72nd		Elected in 1930 to finish Vare's term
						73rd	25	Re-elected in 1932.
25	Joe Guffey	Democratic	Jan 3, 1935 – Jan 3, 1947	Elected in 1934.	26	74th
						75th
						76th	26	Re-elected in 1938. Lost re-election.
				Re-elected in 1940. Lost re-election.	27	77th
						78th
						79th	27	Elected in 1944. Lost re-election.	Jan 3, 1945 – Jan 3, 1951	Democratic	Francis Myers	21
26	Edward Martin	Republican	Jan 3, 1947 – Jan 3, 1959	Elected in 1946.	28	80th
						81st
						82nd	28	Elected in 1950. Lost re-election.	Jan 3, 1951 – Jan 3, 1957	Republican	James H. Duff	22
				Re-elected in 1952. Retired.	29	83rd
						84th
						85th	29	Elected in 1956.	Jan 3, 1957 – Jan 3, 1969	Democratic	Joseph S. Clark Jr.	23
27	Hugh Scott	Republican	Jan 3, 1959 – Jan 3, 1977	Elected in 1958.	30	86th
						87th
						88th	30	Re-elected in 1962. Lost re-election.
				Re-elected in 1964.	31	89th
						90th
						91st	31	Elected in 1968.	Jan 3, 1969 – Jan 3, 1981	Republican	Richard Schweiker	24
				Re-elected in 1970. Retired.	32	92nd
						93rd
						94th	32	Re-elected in 1974. Retired.
28	John Heinz	Republican	Jan 3, 1977 – Apr 4, 1991	Elected in 1976.	33	95th
						96th
						97th	33	Elected in 1980.	Jan 3, 1981 – Jan 3, 2011	Republican	Arlen Specter	25
				Re-elected in 1982.	34	98th
						99th
						100th	34	Re-elected in 1986.
				Re-elected in 1988. Died.	35	101st
				Re-elected in 1988. Died.		102nd
Vacant			Apr 4, 1991 – May 9, 1991
29	Harris Wofford	Democratic	May 9, 1991 – Jan 3, 1995	Appointed to continue Heinz's term. Elected to finish Heinz's term. Lost re-election.
29	Harris Wofford	Democratic	May 9, 1991 – Jan 3, 1995			103rd	35	Re-elected in 1992.
30	Rick Santorum	Republican	Jan 3, 1995 – Jan 3, 2007	Elected in 1994.	36	104th
						105th
						106th	36	Re-elected in 1998.
				Re-elected in 2000. Lost re-election.	37	107th
						108th
						109th	37	Re-elected in 2004. Changed party on Apr 28, 2009. Lost renomination.
31	Bob Casey Jr.	Democratic	Jan 3, 2007 – present	Elected in 2006.	38	110th
						111th
						111th				Democratic
						112th	38	Elected in 2010.	Jan 3, 2011 – Jan 3, 2023	Republican	Pat Toomey	26
				Re-elected in 2012.	39	113th
						114th
						115th	39	Re-elected in 2016. Retired.
				Re-elected in 2018. Lost re-election.	40	116th
						117th
						118th	40	Elected in 2022.	Jan 3, 2023 – present	Democratic	John Fetterman	27
32	David McCormick	Republican	Taking office Jan 3, 2025	Elected in 2024.	41	119th
						120th
						121st	41	To be determined in the 2028 election.
#	Senator	Party	Years in office	Electoral history	T	C	T	Electoral history	Years in office	Party	Senator	#
Class 1						C	Class 3

Notes

^ "Pennsylvania 1809 U.S. Senate, Special". Tufts Digital Collations and Archives. A New Nation Votes: American Election Returns 1787–1825. Tufts University. Retrieved February 3, 2018., citing Journal of the Pennsylvania House of Representatives, 1808, pp. 174–176.
^ "U.S. Senate Election - 13 Dec 1808" (PDF). Wilkes University. Retrieved December 21, 2012.
^ "Pennsylvania 1812 U.S. Senate". Tufts Digital Collations and Archives. A New Nation Votes: American Election Returns 1787–1825. Tufts University. Retrieved February 23, 2018., citing Journal of the Pennsylvania State Senate, 1812, pp. 41–43.
^ Byrd, p. 159.
^ The World Almanac and Encyclopedia 1906. New York: The Press Publishing Co. New York World. 1905. p. 108.