# 2024 United States Senate election in Pennsylvania

Elections in Pennsylvania :
Federal government
U.S. President
1789
1792
1796
1800
1804
1808
1812
1816
1820
1824
1828
1832
1836
1840
1844
1848
1852
1856
1860
1864
1868
1872
1876
1880
1884
1888
1892
1896
1900
1904
1908
1912
1916
1920
1924
1928
1932
1936
1940
1944
1948
1952
1956
1960
1964
1968
1972
1976
1980
1984
1988
1992
1996
2000
2004
2008
2012
2016
2020
2024
Presidential primaries
Democratic
2000
2004
2008
2016
2020
2024
Republican
2008
2016
2020
2024
U.S. Senate
1788
1791
1793 sp
1794 sp
1795
1796
1797
1801
1801 sp
1802
1806
1808
1808 sp
1809 sp
1812
1814
1814 sp
1818
1820
1824
1826
1830
1831 sp
1832
1834 sp
1836
1840 sp
1843
1845
1845 sp
1849
1851
1856
1857
1861
1861 sp
1863
1867
1869
1873
1875
1877 sp
1879
1881
1885
1887
1891
1893
1897
1899
1901 sp
1903
1905
1905 sp
1908
1909
1909 sp
1911
1914
1916
1920
1922
1922 sp
1926
1928
1930 sp
1932
1934
1938
1940
1944
1946
1950
1952
1956
1958
1962
1964
1968
1970
1974
1976
1980
1982
1986
1988
1991 sp
1992
1994
1998
2000
2004
2006
2010
2012
2016
2018
2022
2024
2028
U.S. House of Representatives
1788
1791
1792
1794
1796
5th sp
1797
5th sp
1798
1st sp
4th sp
1800
8th sp
1801
4th sp
8th sp
12th sp
1802
1804
10th sp
1805
4th sp
11th sp
1806
1st sp
1808
1st sp
1809
1st sp
1810
1812
1813
3rd sp
5th sp
7th sp
13th sp
15th sp
1814
2nd sp
3rd sp
1815
1st sp
3rd sp
9th sp
1816
9th sp
1817
10th sp
1818
4th sp
6th sp
1820
5th sp
7th sp
1821
5th sp
10th sp
1822
1st sp
6th sp
7th sp
14th sp
1824
8th sp
13th sp
1825
16th sp
1826
2nd sp
7th sp
13th sp
18th sp
1827
2nd sp
1828
1829
8th sp
16th sp
1830
1831
11th sp
1832
1833
1st sp
1834
1836
13th sp
24th sp
1837
3rd sp
1838
9th sp
1839
14th sp
1840
13th sp
22nd sp
1841
2nd sp
13th sp
20th sp
18th sp
Jun
Dec
1842
17th sp
21st sp
1843
1844
12th sp
13th sp
21st sp
1846
1848
6th sp
1850
11th sp
15th sp
1852
1854
8th sp
1856
1857
12th sp
1858
8th sp
1860
8th sp
1861
2nd sp
12th sp
1862
7th sp
1864
1866
1867
12th sp
1868
9th sp
20th sp
1870
1872
13th sp
1874
23rd sp
1876
12th sp
1878
1880
1882
1884
19th sp
1885
19th sp
1886
1888
1890
3rd sp
4th sp
1892
1893
2nd sp
8th sp
1894
at-large sp
1895
15th sp
1896
1897
25th sp
1898
23rd sp
1899
9th sp
1900
5th sp
1901
10th sp
1902
17th sp
1903
4th sp
1904
3rd sp
1906
2nd sp
3rd sp
12th sp
1907
2nd sp
1908
1910
1911
2nd sp
14th sp
1912
1st sp
1914
1916
1917
28th sp
1918
1919
22nd sp
1920
3rd sp
1921
at-large sp
1922
1924
1926
1927
1st sp
1928
8th sp
1929
12th sp
1930
1931
2nd sp
1932
6th sp
18th sp
20th sp
1933
9th sp
1934
1936
1937
18th sp
1938
1939
4th sp
1940
1941
15th sp
1942
11th sp
12th sp
33rd sp
1943
2nd sp
23rd sp
1944
2nd sp
17th sp
1946
10th sp
23rd sp
33rd sp
1947
8th sp
1948
1949
22nd sp
26th sp
1950
1951
8th sp
14th sp
33rd sp
1952
1954
1956
2nd sp
30th sp
1957
13th sp
1958
4th sp
21st sp
1960
17th sp
18th sp
1961
16th sp
1962
1963
15th sp
23rd sp
1964
5th sp
1966
1968
1970
9th sp
1971
18th sp
1972
27th sp
1974
12th sp
1976
1st sp
1978
1980
11th sp
12th sp
1981
3rd sp
1982
1984
1986
1988
1990
1991
2nd sp
1992
1994
1996
1998
1st sp
2000
2001
9th sp
2002
2004
2006
2008
2010
12th sp
2012
2014
2016
2nd sp
2018
7th sp
15th sp
18th sp
2019
12th sp
2020
2022
2024 :
State government
Governor
1790
1793
1796
1799
1802
1805
1808
1811
1814
1817
1820
1823
1826
1829
1832
1835
1838
1841
1844
1847
1848
1851
1854
1857
1860
1863
1866
1869
1872
1875
1878
1882
1886
1890
1894
1898
1902
1906
1910
1914
1918
1922
1926
1930
1934
1938
1942
1946
1950
1954
1958
1962
1966
1970
1974
1978
1982
1986
1990
1994
1998
2002
2006
2010
2014
2018
2022
2026
Lieutenant Governor
1874
1878
1882
1886
1890
1894
1898
1902
1906
1910
1914
1918
1922
1926
1930
1934
1938
1942
1946
1950
1954
1958
1962
1966
1970
1974
1978
1982
1986
1990
1994
1998
2002
2006
2010
2014
2018
2022
Attorney General
1980
1984
1988
1992
1996
2000
2004
2008
2012
2016
2020
2024
Auditor General
2000
2004
2008
2012
2016
2020
2024
State Treasurer
2000
2004
2008
2012
2016
2020
2024
State Senate
2000
2002
2004
2006
2008
2010
2012
2014
2016
2018
2020
2022
2024
State House of Representatives
2000
2002
2004
2006
2008
2010
2012
2014
2016
2018
2020
2022
2024 :
Elections by year
State elections
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025 :
Philadelphia
Mayoral elections
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1856
1858
1860
1862
1865
1868
1871
1874
1877
1881
1884
1887
1891
1895
1899
1903
1907
1911
1915
1919
1923
1927
1931
1935
1939
1943
1947
1951
1955
1959
1963
1967
1971
1975
1979
1983
1987
1991
1995
1999
2003
2007
2011
2015
2019
2023
City Council elections
1951
1954 sp.
1955
1959
1963
2015
2019
2022–23 sp.
2023
Other municipal elections
1951
1953
1955
1957
1959
1961
1963
2023 :
Pittsburgh
Mayors
1909
1913
1917
1921
1925
1929
1933
1937
1941
1945
1949
1953
1957
1959
1961
1965
1969
1973
1977
1981
1985
1989
1993
1997
2001
2005
2007
2009
2013
2017
2021
2025 :
Allentown
Mayors
1977
1981
1985
1989
1993
1997
2001
2005
2009
2013
2017
2019 sp
2021
2025 :
Lancaster
Mayors
2009
2017
2021
2025 :
Harrisburg
Mayors
1969
1973
1977
1981
1985
1989
1993
1997
2001
2005
2009
2013
2017
2021
2025 :
Government :
vte :
The 2024 United States Senate election in Pennsylvania was held on November 5, 2024, to elect a member of the United States Senate to represent the state of Pennsylvania. Incumbent Democratic Senator Bob Casey Jr. lost re-election to a fourth term, being defeated by Republican nominee Dave McCormick in what was considered a major upset. Most predictions gave Casey a slight advantage, and Casey narrowly led in most polls. Along with Sherrod Brown in Ohio and Jon Tester in Montana, Casey was one of three incumbent senators to lose re-election in 2024.
The primary election took place on April 23, 2024. The election was considered essential for Democrats' chances to retain their majority in 2024.
The Associated Press and Fox News declared McCormick the winner on November 7, while Decision Desk HQ called the race for McCormick on November 14. CNN, NBC, ABC, and CBS all called the race for McCormick on November 21; Casey conceded the race later that day. A recount confirmed the result.
This was Pennsylvania's closest US Senate election since the passage of the Seventeenth Amendment, as well as the closest Senate election of the 2024 cycle. McCormick was the only Republican challenger to win in a state flipped by Trump in the 2024 presidential election. The other three Republican Senate gains were in states Trump had won in all three of his runs. With Democrats winning the other Senate seat two years earlier, this was the first time since the 2012 Senate election in Indiana where the opposite party flipped a seat after losing one in the previous cycle.
Notably, the margin of just 0.22% between the Republican and Democratic candidates is fewer than the votes received by either the Libertarian candidate, John Thomas (1.29% of the vote), the Green candidate, Leila Hazou (0.95% of the vote), or the Constitution candidate, Marty Selker (0.34% of the vote).
This was Casey's first general election loss of his political career, and the second counting Casey's primary election loss in 2002. This election made Pennsylvania one of several states to have a younger senior senator (John Fetterman) and an older junior senator (McCormick). McCormick was sworn in on January 3, 2025.

## Background

Pennsylvania is considered to be a purple state at the federal level, especially since in the 2020 presidential election, Joe Biden carried Pennsylvania by about 1.2 percentage points. Democrats had controlled both U.S. Senate seats, the governorship, a majority of its U.S. House delegation, and the Pennsylvania House of Representatives. The last time Republicans won a U.S. Senate seat in Pennsylvania was in 2016.
Senator Bob Casey Jr. was first elected in the blue wave of 2006, defeating then-incumbent Senator Rick Santorum by about 17 percentage points. He was re-elected in 2012 by 9 percentage points (when he ran ahead of Obama by almost 4 points) and in the blue wave of 2018 by 13 percentage points. Given these three decisive victories, Casey's fourth term appeared inevitable for much of the race. However, tightening polls in the final weeks indicated a closer contest, even as Casey was largely considered the favorite to win.

## Democratic primary
### Candidates
#### Nominee

* Bob Casey Jr., incumbent U.S. senator (2007–2025)

#### Disqualified

* William Parker, app developer

### Endorsements

Executive officials
* Patrick Murphy, Acting Secretary of the Army (2016), former U.S. representative for PA-8 (2007–2011)
U.S. senators
* John Fetterman, U.S. senator from Pennsylvania (2023–present)
* Mark Kelly, U.S. senator from Arizona (2020–present)
U.S. representatives
* Chris Carney, PA-10 (2007–2011)
* Chris Deluzio, PA-17 (2023–present)
* Chrissy Houlahan, PA-6 (2019–present)
* Conor Lamb, PA-17 (2018–2023)
Statewide officials
* Josh Shapiro, Governor of Pennsylvania (2023–present)
* Gretchen Whitmer, Governor of Michigan (2019-present)
Individuals
* Harry Dunn, former U.S. Capitol Police officer
* Cristina Tzintzún Ramirez, labor organizer and president of NextGen America PAC (2021–present)
Political parties
* Pennsylvania Democratic Party
Organizations
* American Israel Public Affairs Committee (AIPAC)
* CASA in Action
* Council for a Livable World
* Democratic Majority for Israel
* End Citizens United
* Feminist Majority PAC
* Giffords
* Harvard College Democrats
* Human Rights Campaign
* Humane Society Legislative Fund
* Jewish Democratic Council of America
* Joint Action Committee for Political Affairs
* League of Conservation Voters
* National Committee to Preserve Social Security and Medicare
* Natural Resources Defense Council
* NextGen America PAC
* Peace Action
* Pennsylvania State Education Association
* People for the American Way
* Swing Left
Labor unions
* Actors' Equity Association
* AFSCME Council 13
* Association of Flight Attendants
* National Education Association
* Pennsylvania AFL–CIO
* United Mine Workers of America
* United Steelworkers
Newspapers
* Philadelphia Gay News

### Fundraising

Campaign finance reports as of April 15, 2024 :
| Candidate | Raised | Spent | Cash on hand |
| Bob Casey Jr. (D) | $23,790,263 | $12,391,802 | $11,886,480 |
| Source: Federal Election Commission ||||

### Results

Democratic primary results :
| Party | Party | Candidate | Votes | % |
| | Democratic | Bob Casey Jr. (incumbent) | 1,024,545 | 100.00% |
| Total votes | Total votes | Total votes | 1,024,545 | 100.00% |

## Republican primary
### Candidates
#### Nominee

* Dave McCormick, former U.S. Under Secretary of the Treasury for International Affairs (2007–2009), former CEO of Bridgewater Associates (2020–2022), and candidate for U.S. Senate in 2022

#### Withdrawn

* Brandi Tomasetti, former Conestoga Township treasurer and secretary (ran as a write-in candidate)

#### Disqualified

* Joseph Vodvarka, spring manufacturer and perennial candidate

#### Declined

* Kathy Barnette, political commentator, nominee for Pennsylvania's 4th congressional district in 2020, and candidate for U.S. Senate in 2022
* Stacy Garrity, Pennsylvania State Treasurer (2021–present) (running for re-election)
* Doug Mastriano, state senator for SD-33 (2019–present) and nominee for Governor of Pennsylvania in 2022 (endorsed McCormick)

### Endorsements

Executive Branch officials
* George W. Bush, 43rd President of the United States (2001–2009)
* Karl Rove, former White House Deputy Chief of Staff for Policy (2005–2007)
* Donald Trump, 45th President of the United States (2017–2021) and Republican presidential candidate
Federal officials
* John Bolton, former National Security Advisor (2018–2019) and former Ambassador to the United Nations (2005–2006)
* Dina Powell, former Deputy National Security Advisor for Strategy (2017–2018) (his wife)
State cabinet officials
* Robert Gleason, former Pennsylvania Secretary of the Commonwealth (1985–1987)
U.S senators
* Pat Toomey, U.S. senator from Pennsylvania (2011–2023)
* Rick Santorum, U.S. senator from Pennsylvania (1995–2007)
* Marsha Blackburn, U.S. senator from Tennessee (2019–present)
* Steve Daines, U.S. senator from Montana (2015–present)
* Mitch McConnell, U.S. senator from Kentucky (1985–present) and Senate Minority Leader (2007–2015, 2021–2025)
U.S. representatives
* Brian Fitzpatrick, PA-1 (2017–present)
* Jim Jordan, OH-4 (2007–present)
* John Joyce, PA-13 (2019–present)
* Mike Kelly, PA-16 (2011–present)
* Dan Meuser, PA-9 (2019–present)
* Scott Perry, PA-10 (2013–present)
* Guy Reschenthaler, PA-14 (2019–present)
* Lloyd Smucker, PA-11 (2017–present)
* Glenn Thompson, PA-15 (2009–present)
State senators
* Ryan Aument, state senator for SD-36 (2015–2024)
* Doug Mastriano, state senator for SD-33 (2019–present) and 2022 GOP nominee for Governor
Local officials
* Sam DeMarco, at-large Allegheny County councilor (2016–present) and chair of the Allegheny County Republican Party (2018–present)
Party officials
* Andrew Reilly, Republican National Committeeman from Pennsylvania (2020–present)
* Christine Toretti, Republican National Committeewoman from Pennsylvania (1997–present)
Organizations
* Americans for Prosperity
* Conservative Political Action Conference
* Log Cabin Republicans
* Pennsylvania Federation and Penn State College Republicans
* Republican Jewish Coalition
Political parties
* Pennsylvania Republican Party
Individuals
* Kenneth C. Griffin, businessman
* Paul Tudor Jones, philanthropist
* Matt Schlapp, chair of the American Conservative Union (2014–present)
* Charles R. Schwab, investor

### Fundraising

Campaign finance reports as of April 15, 2024 :
| Candidate | Raised | Spent | Cash on hand |
| Dave McCormick (R) | $11,052,879 | $4,660,701 | $6,399,998 |
| Source: Federal Election Commission ||||

### Polling

| Poll source | Date(s) administered | Sample size | Margin of error | Kathy Barnette | Doug Mastriano | David McCormick | Undecided |
| Public Policy Polling (D) | March 9–10, 2023 | 616 (LV) | – | 11% | 39% | 21% | 29% |
| Public Policy Polling (D) | March 9–10, 2023 | 616 (LV) | – | – | 42% | 28% | 29% |

### Results

Republican primary results :
| Party | Party | Candidate | Votes | % |
| | Republican | Dave McCormick | 878,320 | 100.00% |
| Total votes | Total votes | Total votes | 878,320 | 100.00% |

## Third parties
### Libertarian convention
#### Nominee

* John Thomas, educator

#### Eliminated at convention

* Erik Gerhardt, carpenter, nominee for U.S. Senate in 2022, and candidate for president in 2020

### Green Party
#### Nominee

* Leila Hazou, shop owner

### Constitution Party
#### Nominee

* Bernard Selker, truck driver

### American Solidarity Party
#### Disqualified

* Erik Messina

## General election
### Predictions

| Source | Ranking | As of |
| The Cook Political Report | Tossup | October 21, 2024 |
| Inside Elections | Tilt D | November 9, 2023 |
| Sabato's Crystal Ball | Lean D | June 13, 2024 |
| Decision Desk HQ/The Hill | Tossup | June 8, 2024 |
| Elections Daily | Lean D | October 24, 2024 |
| CNalysis | Lean D | November 21, 2023 |
| RealClearPolitics | Tossup | August 5, 2024 |
| Split Ticket | Lean D | October 23, 2024 |
| 538 | Lean D | October 28, 2024 |

### Post-primary endorsements

Executive branch officials
* Joe Biden, 46th President of the United States (2021–2025), 47th Vice President of the United States (2009–2017)
* Kamala Harris, 49th Vice President of the United States (2021–2025)
* Barack Obama, 44th President of the United States (2009–2017)
Former U.S. executive officials
* Nikki Haley, United States Ambassador to the United Nations (2017–2018) and Governor of South Carolina (2011–2017)
U.S. Senators
* John Thune, Senate Minority Whip (2021–2025) from South Dakota (2005–present)
Individuals
* Elon Musk, CEO of Tesla and SpaceX
Individuals
* Ben Zeisloft, Christian conservative commentator for The Daily Wire
* Bill Cox, Pennsylvania state director for Robert F. Kennedy Jr.'s presidential campaign

### Fundraising

Campaign finance reports as of October 16, 2024 :
| Candidate | Raised | Spent | Cash on hand |
| Bob Casey (D) | $52,879,737 | $50,545,793 | $2,821,961 |
| Dave McCormick (R) | $27,698,652 | $26,030,736 | $1,675,736 |
| Source: Federal Election Commission ||||

### Debates

2024 Pennsylvania U.S. Senate election debates :
| No. | Date | Host | Moderator | Link | Democratic | Republican |
| Key: P Participant  A Absent  N Not invited  I Invited W Withdrawn | Key: P Participant  A Absent  N Not invited  I Invited W Withdrawn | Key: P Participant  A Absent  N Not invited  I Invited W Withdrawn | Key: P Participant  A Absent  N Not invited  I Invited W Withdrawn | Key: P Participant  A Absent  N Not invited  I Invited W Withdrawn | | |
| Key: P Participant  A Absent  N Not invited  I Invited W Withdrawn | Key: P Participant  A Absent  N Not invited  I Invited W Withdrawn | Key: P Participant  A Absent  N Not invited  I Invited W Withdrawn | Key: P Participant  A Absent  N Not invited  I Invited W Withdrawn | Key: P Participant  A Absent  N Not invited  I Invited W Withdrawn | Casey | McCormick |
| 1 | October 3, 2024 | WHTM-TV | Dennis Owens | YouTube | P | P |
| 2 | October 15, 2024 | WPVI-TV | Matt O'Donnell, Sharrie Williams, Ilia Garcia | C-SPAN | P | P |

### Polling

Aggregate polls
| Source of poll aggregation | Dates administered | Dates updated | Bob Casey Jr. (D) | Dave McCormick (R) | Undecided | Margin |
| 538 | through November 4, 2024 | November 4, 2024 | 48.2% | 45.4% | 6.4% | Casey +2.8% |
| RealClearPolitics | October 21 – November 4, 2024 | November 4, 2024 | 48.1% | 46.3% | 5.6% | Casey +1.8% |
| 270toWin | October 24 – November 4, 2024 | November 4, 2024 | 48.4% | 45.9% | 5.7% | Casey +2.5% |
| TheHill/DDHQ | through November 4, 2024 | November 4, 2024 | 48.6% | 46.6% | 4.8% | Casey +2.0% |
| Average | Average | Average | 48.3% | 46.1% | 5.6% | Casey +2.2% |
| Poll source | Date(s) administered | Sample size | Margin of error | Bob Casey Jr. (D) | Dave McCormick (R) | Other | Undecided |
| AtlasIntel | November 3–4, 2024 | 1,840 (LV) | ± 2.0% | 49% | 47% | 2% | 2% |
| Survation | November 1–4, 2024 | 929 (LV) | – | 49% | 42% | 3% | 6% |
| Research Co. | November 2–3, 2024 | 450 (LV) | ± 4.6% | 48% | 46% | 2% | 4% |
| Patriot Polling (R) | November 1–3, 2024 | 903 (RV) | ± 3.0% | 50% | 49% | – | – |
| The Trafalgar Group (R) | November 1–3, 2024 | 1,089 (LV) | ± 2.9% | 46% | 47% | – | 7% |
| InsiderAdvantage (R) | November 1–2, 2024 | 800 (LV) | ± 3.5% | 48% | 47% | 2% | 3% |
| AtlasIntel | November 1–2, 2024 | 2,049 (LV) | ± 2.0% | 49% | 47% | 3% | 2% |
| Emerson College | October 30 – November 2, 2024 | 1,000 (LV) | ± 3.0% | 47% | 47% | – | 6% |
| New York Times/Siena College | October 29 – November 2, 2024 | 1,527 (LV) | ± 2.9% | 50% | 45% | – | 4% |
| New York Times/Siena College | October 29 – November 2, 2024 | 1,527 (RV) | ± 2.8% | 50% | 45% | – | 6% |
| Mainstreet Research/FAU | October 25 – November 2, 2024 | 699 (LV) | ± 3.6% | 49% | 44% | 1% | 6% |
| Mainstreet Research/FAU | October 25 – November 2, 2024 | 726 (RV) | ± 3.6% | 48% | 43% | 2% | 7% |
| Morning Consult | October 23 – November 1, 2024 | 1,538 (LV) | ± 3.0% | 46% | 43% | – | 11% |
| AtlasIntel | October 30–31, 2024 | 1,738 (LV) | ± 2.0% | 49% | 46% | 3% | 2% |
| OnMessage (R) | October 29–31, 2024 | 800 (LV) | – | 46% | 46% | – | 8% |
| Data for Progress (D) | October 25–31, 2024 | 908 (LV) | ± 3.0% | 49% | 45% | 2% | 4% |
| YouGov | October 25–31, 2024 | 947 (LV) | ± 3.5% | 50% | 44% | – | 6% |
| YouGov | October 25–31, 2024 | 982 (RV) | ± 3.5% | 50% | 43% | – | 6% |
| ActiVote | October 14–31, 2024 | 400 (LV) | ± 4.9% | 50.5% | 49.5% | – | – |
| Muhlenberg College | October 27–30, 2024 | 460 (LV) | ± 6.0% | 49% | 46% | 3% | 1% |
| Suffolk University | October 27–30, 2024 | 500 (LV) | ± 4.4% | 49% | 46% | 2% | 2% |
| Marist College | October 27–30, 2024 | 1,400 (LV) | ± 3.4% | 50% | 48% | 1% | 1% |
| Marist College | October 27–30, 2024 | 1,558 (RV) | ± 3.2% | 50% | 48% | 1% | 1% |
| Echelon Insights | October 27–30, 2024 | 600 (LV) | ± 4.5% | 44% | 47% | 3% | 5% |
| The Washington Post | October 26–30, 2024 | 1,204 (LV) | ± 3.1% | 49% | 46% | 2% | 3% |
| The Washington Post | October 26–30, 2024 | 1,204 (RV) | ± 3.1% | 49% | 45% | 3% | 3% |
| AtlasIntel | October 25–29, 2024 | 1,229 (LV) | ± 3.0% | 49% | 47% | 3% | 2% |
| Fox News | October 24–28, 2024 | 1,057 (LV) | ± 3.0% | 50% | 48% | – | 1% |
| Fox News | October 24–28, 2024 | 1,310 (RV) | ± 2.5% | 51% | 46% | 1% | 2% |
| Quinnipiac University | October 24–28, 2024 | 2,186 (LV) | ± 2.1% | 50% | 47% | 2% | 1% |
| Monmouth University | October 24–28, 2024 | 824 (RV) | ± 3.8% | 45% | 44% | – | 12% |
| CNN/SSRS | October 23–28, 2024 | 819 (LV) | ± 4.7% | 48% | 45% | 6% | 1% |
| CBS News/YouGov | October 22–28, 2024 | 1,249 (LV) | ± 3.6% | 48% | 42% | 3% | 7% |
| InsiderAdvantage (R) | October 26–27, 2024 | 800 (LV) | ± 3.5% | 47% | 47% | 2% | 4% |
| North Star Opinion Research (R) | October 22–26, 2024 | 600 (LV) | ± 4.0% | 45% | 42% | 5% | 9% |
| UMass Lowell/YouGov | October 16–23, 2024 | 800 (LV) | ± 3.7% | 48% | 42% | 3% | 7% |
| Emerson College | October 21–22, 2024 | 860 (LV) | ± 3.3% | 47% | 46% | 2% | 6% |
| Susquehanna Polling & Research (R) | October 18–22, 2024 | 500 (LV) | ± 4.4% | 49% | 46% | 2% | 4% |
| Franklin & Marshall College | October 9–20, 2024 | 583 (LV) | ± 5.0% | 49% | 48% | – | 3% |
| Franklin & Marshall College | October 9–20, 2024 | 794 (RV) | ± 4.3% | 48% | 41% | 5% | 6% |
| The Trafalgar Group (R) | October 17–19, 2024 | 1,084 (LV) | ± 2.9% | 47% | 47% | – | 6% |
| AtlasIntel | October 12–17, 2024 | 2,048 (LV) | ± 2.0% | 47% | 48% | 2% | 3% |
| The Bullfinch Group | October 11–17, 2024 | 600 (LV) | ± 4.0% | 50% | 43% | – | 8% |
| YouGov | October 7–17, 2024 | 1,043 (LV) | ± 3.44% | 50% | 42% | – | 8% |
| YouGov | October 7–17, 2024 | 1,062 (RV) | ± 3.4% | 49% | 42% | – | 9% |
| Morning Consult | October 6–15, 2024 | 1,395 (LV) | ± 3.0% | 49% | 41% | – | 10% |
| New York Times/Siena College | October 7–10, 2024 | 857 (LV) | ± 3.8% | 48% | 44% | – | 8% |
| New York Times/Siena College | October 7–10, 2024 | 857 (RV) | ± 3.7% | 48% | 43% | – | 9% |
| American Pulse Research & Polling | October 2–10, 2024 | 1,193 (LV) | ± 2.8% | 48% | 45% | 2% | 5% |
| TIPP Insights (R) | October 7–9, 2024 | 803 (LV) | ± 3.5% | 47% | 43% | 1% | 9% |
| TIPP Insights (R) | October 7–9, 2024 | 1,079 (RV) | ± 3.5% | 48% | 40% | 1% | 12% |
| UMass Lowell/YouGov | October 2–9, 2024 | 800 (LV) | ± 4.0% | 48% | 39% | 3% | 10% |
| InsiderAdvantage (R) | October 7–8, 2024 | 800 (LV) | ± 3.5% | 47% | 45% | 2% | 6% |
| Emerson College | October 5–8, 2024 | 1,000 (LV) | ± 3.0% | 48% | 46% | – | 6% |
| Research Co. | October 5–7, 2024 | 450 (LV) | ± 4.6% | 47% | 44% | 1% | 8% |
| Quinnipiac University | October 3–7, 2024 | 1,412 (LV) | ± 2.6% | 51% | 43% | 2% | 5% |
| ActiVote | September 6 – October 7, 2024 | 400 (LV) | ± 4.9% | 53% | 47% | – | – |
| OnMessage (R) | September 28–29, 2024 | 800 (LV) | ± 3.5% | 45% | 44% | 5% | 7% |
| Patriot Polling (R) | September 27–29, 2024 | 816 (RV) | ± 3.0% | 51% | 48% | – | – |
| The Bullfinch Group | September 26–29, 2024 | 800 (LV) | ± 3.46% | 48% | 39% | 12% | – |
| The Bullfinch Group | September 26–29, 2024 | 800 (LV) | ± 3.46% | 52% | 42% | 6% | – |
| The Trafalgar Group (R) | September 26–29, 2024 | 1,090 (LV) | ± 2.9% | 47% | 46% | – | 7% |
| Emerson College | September 27–28, 2024 | 1,000 (LV) | ± 3.0% | 47% | 45% | – | 8% |
| AtlasIntel | September 20–25, 2024 | 1,775 (LV) | ± 2.0% | 47% | 45% | 1% | 6% |
| BSG (R)/GS Strategy Group (D) | September 19–25, 2024 | 474 (LV) | – | 48% | 42% | 3% | 6% |
| BSG (R)/GS Strategy Group (D) | September 19–25, 2024 | 474 (LV) | – | 52% | 45% | – | 3% |
| Fox News | September 20–24, 2024 | 775 (LV) | ± 3.5% | 53% | 44% | 1% | 2% |
| Fox News | September 20–24, 2024 | 1,021 (RV) | ± 3.0% | 53% | 44% | 1% | 2% |
| Fabrizio Ward (R)/Impact Research (D) | September 17–24, 2024 | 816 (RV) | ± 3.0% | 49% | 45% | – | 6% |
| Susquehanna Polling & Research (R) | September 16–22, 2024 | 700 (LV) | ± 3.7% | 48% | 40% | 1% | 11% |
| RMG Research | September 18–20, 2024 | 783 (LV) | ± 3.5% | 50% | 44% | 1% | 5% |
| Remington Research Group (R) | September 16–20, 2024 | 800 (LV) | ± 3.5% | 49% | 45% | – | 7% |
| Muhlenberg College | September 16–19, 2024 | 450 (LV) | ± 6.0% | 48% | 43% | 5% | 4% |
| Redfield & Wilton Strategies | September 16–19, 2024 | 1,086 (LV) | ± 2.8% | 47% | 41% | 2% | 10% |
| UMass Lowell/YouGov | September 11–19, 2024 | 800 (LV) | ± 4.0% | 47% | 38% | 3% | 13% |
| Emerson College | September 15–18, 2024 | 880 (LV) | ± 3.2% | 47% | 42% | – | 11% |
| MassINC Polling Group | September 12–18, 2024 | 800 (LV) | ± 4.0% | 49% | 42% | 2% | 6% |
| Morning Consult | September 9–18, 2024 | 1,756 (LV) | ± 3.0% | 49% | 40% | – | 11% |
| Marist College | September 12–17, 2024 | 1,663 (RV) | ± 2.0% | 52% | 46% | 1% | 1% |
| Marist College | September 12–17, 2024 | 1,476 (LV) | ± 3.2% | 52% | 47% | – | 1% |
| Quinnipiac University | September 12–16, 2024 | 1,331 (LV) | ± 2.7% | 52% | 43% | 1% | 3% |
| The Washington Post | September 12–16, 2024 | 1,003 (LV) | ± 3.6% | 47% | 46% | 7% | – |
| The Washington Post | September 12–16, 2024 | 1,003 (LV) | ± 3.6% | 48% | 48% | 5% | – |
| New York Times/Siena College | September 11–16, 2024 | 1,082 (RV) | ± 4.1% | 48% | 39% | – | 13% |
| New York Times/Siena College | September 11–16, 2024 | 1,082 (LV) | ± 4.3% | 49% | 40% | – | 11% |
| InsiderAdvantage (R) | September 14–15, 2024 | 800 (LV) | ± 3.5% | 49% | 44% | 2% | 5% |
| Franklin & Marshall College | September 4–15, 2024 | 890 (RV) | ± 4.1% | 48% | 40% | 3% | 10% |
| Suffolk University | September 11–14, 2024 | 500 (LV) | ± 4.4% | 47% | 43% | 2% | 8% |
| Redfield & Wilton Strategies | September 6–9, 2024 | 801 (LV) | ± 3.0% | 44% | 36% | 5% | 14% |
| Morning Consult | August 30 – September 8, 2024 | 1,910 (LV) | ± 2.0% | 49% | 40% | – | 11% |
| co/efficient (R) | September 4–6, 2024 | 889 (LV) | ± 3.29% | 45% | 36% | – | 19% |
| CBS News/YouGov | September 3–6, 2024 | 1,076 (LV) | ± 3.4% | 48% | 41% | 3% | 8% |
| YouGov | August 23 – September 3, 2024 | 1,000 (RV) | ± 3.6% | 52% | 41% | – | 8% |
| The Trafalgar Group (R) | August 28–30, 2024 | 1,082 (LV) | ± 2.9% | 46% | 45% | – | 8% |
| CNN/SRSS | August 23–29, 2024 | 789 (LV) | ± 4.7% | 46% | 46% | 7% | 1% |
| Redfield & Wilton Strategies | August 25–28, 2024 | 1,071 (LV) | ± 2.8% | 44% | 38% | 4% | 14% |
| Emerson College | August 25–28, 2024 | 950 (LV) | ± 3.1% | 48% | 44% | – | 8% |
| SoCal Strategies (R) | August 23, 2024 | 713 (LV) | – | 47% | 41% | – | 12% |
| 800 (RV) | August 23, 2024 | – | 45% | 40% | – | 15% |
| ActiVote | August 3–23, 2024 | 400 (LV) | ± 4.9% | 55% | 45% | – | – |
| Fabrizio Ward (R) | August 19–21, 2024 | 400 (LV) | ± 4.9% | 46% | 43% | – | 11% |
| Cygnal (R) | August 14–15, 2024 | 800 (LV) | ± 3.4% | 46% | 42% | – | 12% |
| 42% | August 14–15, 2024 | 800 (LV) | ± 3.4% | 38% | 7% | 13% |
| Redfield & Wilton Strategies | August 12–15, 2024 | 825 (LV) | ± 3.2% | 44% | 36% | 1% | 17% |
| Emerson College | August 13–14, 2024 | 1,000 (LV) | ± 3.0% | 48% | 44% | – | 8% |
| Quinnipiac University | August 8–12, 2024 | 1,738 (LV) | ± 2.4% | 52% | 44% | 1% | 3% |
| The Bullfinch Group | August 8–11, 2024 | 500 (RV) | ± 4.38% | 51% | 39% | – | 10% |
| Franklin & Marshall College | July 31 – August 11, 2024 | 920 (RV) | ± 3.8% | 48% | 36% | 3% | 13% |
| New York Times/Siena College | August 6–9, 2024 | 693 (RV) | ± 4.0% | 50% | 36% | – | 14% |
| 693 (LV) | ± 4.2% | 51% | 37% | – | 11% |
| Redfield & Wilton Strategies | July 31 – August 3, 2024 | 743 (LV) | ± 3.4% | 45% | 40% | 2% | 12% |
| BSG (R)/GS Strategy Group (D) | July 26 – August 2, 2024 | 411 (LV) | – | 53% | 40% | – | 7% |
| Susquehanna Polling & Research (R) | July 22–28, 2024 | 600 (LV) | ± 4.0% | 47% | 42% | – | 11% |
| Fox News | July 22–24, 2024 | 1,034 (RV) | ± 3.0% | 55% | 42% | – | 1% |
| Redfield & Wilton Strategies | July 22–24, 2024 | 851 (LV) | ± 3.1% | 46% | 39% | 4% | 11% |
| Emerson College | July 22–23, 2024 | 850 (RV) | ± 3.3% | 48% | 44% | – | 8% |
| SoCal Strategies (R) | July 20–21, 2024 | 500 (LV) | ± 4.4% | 50% | 40% | – | 10% |
| Public Policy Polling (D) | July 17–18, 2024 | 624 (RV) | ± 3.8% | 50% | 39% | – | 11% |
| Redfield & Wilton Strategies | July 16–18, 2024 | 688 (LV) | – | 44% | 37% | 3% | 15% |
| Public Policy Polling (D) | July 11–12, 2024 | 537 (RV) | – | 47% | 44% | – | 9% |
| YouGov | July 4–12, 2024 | 1,000 (RV) | ± 3.4% | 50% | 38% | 1% | 11% |
| 889 (LV) | – | 51% | 39% | 1% | 9% |
| New York Times/Siena College | July 9–11, 2024 | 872 (RV) | ± 3.7% | 50% | 39% | – | 10% |
| 872 (LV) | ± 3.8% | 50% | 42% | – | 8% |
| Expedition Strategies | June 24 – July 8, 2024 | 284 (LV) | – | 48% | 45% | – | 7% |
| Remington Research Group (R) | June 29 – July 1, 2024 | 673 (LV) | ± 4.0% | 49% | 48% | – | 4% |
| Cygnal (R) | June 27–28, 2024 | 800 (LV) | ± 3.5% | 46% | 42% | – | 12% |
| The Bullfinch Group | June 14–19, 2024 | 800 (RV) | ± 3.5% | 48% | 36% | – | 16% |
| Emerson College | June 13–18, 2024 | 1,000 (RV) | ± 3.0% | 47% | 41% | – | 12% |
| Marist College | June 3–6, 2024 | 1,181 (RV) | ± 3.6% | 52% | 46% | – | 2% |
| Mainstreet Research/FAU | May 30–31, 2024 | 1,012 (RV) | ± 3.1% | 48% | 40% | 5% | 7% |
| Mainstreet Research/FAU | May 30–31, 2024 | 923 (LV) | ± 3.1% | 49% | 42% | 3% | 6% |
| KAConsulting (R) | May 15–19, 2024 | 600 (RV) | – | 47% | 37% | 4% | 12% |
| BSG (R)/GS Strategy Group (D) | May 6–13, 2024 | 730 (LV) | ± 3.6% | 49% | 41% | – | 10% |
| New York Times/Siena College | April 28 – May 9, 2024 | 1,023 (RV) | ± 3.6% | 46% | 41% | – | 13% |
| New York Times/Siena College | April 28 – May 9, 2024 | 1,023 (LV) | ± 3.6% | 46% | 44% | – | 10% |
| Fabrizio Ward (R)/Impact Research (D) | April 24–30, 2024 | 1,398 (LV) | ± 3.0% | 48% | 44% | – | 8% |
| Emerson College | April 25–29, 2024 | 1,000 (RV) | ± 3.0% | 46% | 42% | – | 12% |
| CBS News/YouGov | April 19–25, 2024 | 1,306 (LV) | ± 3.1% | 46% | 39% | – | 15% |
| Muhlenberg College | April 15–25, 2024 | 417 (RV) | ± 6.0% | 45% | 41% | 5% | 9% |
| The Bullfinch Group | March 29 – April 3, 2024 | 600 (RV) | ± 4.0% | 45% | 38% | 9% | 8% |
| National Public Affairs | March 2024 | 759 (LV) | ± 3.6% | 32% | 28% | – | 40% |
| Franklin & Marshall College | March 20–31, 2024 | 431 (RV) | ± 5.7% | 46% | 39% | – | 15% |
| The Bullfinch Group | March 22–26, 2024 | 800 (RV) | ± 3.5% | 47% | 30% | 8% | 15% |
| Emerson College | March 10–13, 2024 | 1,000 (RV) | ± 3.0% | 52% | 48% | – | – |
| Susquehanna Polling & Research (R) | February 27 – March 7, 2024 | 450 (LV) | ± 4.6% | 48% | 42% | – | 10% |
| Emerson College | February 14–16, 2024 | 1,000 (RV) | ± 3.0% | 49% | 39% | – | 13% |
| Chism Strategies | February 6–8, 2024 | 500 (RV) | ± 5.0% | 38% | 37% | – | 25% |
| Public Opinion Strategies (R) | January 22–25, 2024 | 800 (LV) | ± 3.5% | 47% | 40% | – | 12% |
| Franklin & Marshall College | January 17–28, 2024 | 1,006 (RV) | ± 3.6% | 47% | 35% | 4% | 14% |
| Susquehanna Polling & Research (R) | January 15–21, 2024 | 745 (LV) | ± 3.7% | 46% | 42% | 3% | 9% |
| Quinnipiac University | January 4–8, 2024 | 1,680 (RV) | ± 2.4% | 53% | 43% | 1% | 2% |
| The Bullfinch Group | December 8–12, 2023 | 800 (RV) | ± 3.5% | 42% | 27% | 13% | 20% |
| Change Research (D) | December 3–7, 2023 | 2,532 (RV) | ± 3.5% | 44% | 41% | 0% | 15% |
| Franklin & Marshall College | October 11–22, 2023 | 873 (RV) | ± 4.1% | 46% | 39% | 4% | 12% |
| Emerson College | October 1–4, 2023 | 430 (RV) | ± 4.7% | 41% | 33% | 8% | 18% |
| Quinnipiac University | September 28 – October 2, 2023 | 1,725 (RV) | ± 2.4% | 50% | 44% | 2% | 4% |
| Susquehanna Polling & Research (R) | May 2–8, 2023 | 700 (LV) | ± 3.7% | 53% | 41% | 1% | 5% |
| Cygnal (R) | April 12–13, 2023 | 600 (LV) | ± 4.0% | 46% | 41% | 0% | 13% |
| Franklin & Marshall College | March 27 – April 7, 2023 | 643 (RV) | ± 6.6% | 42% | 35% | – | 23% |
Bob Casey Jr. vs. Doug Mastriano
| Poll source | Date(s) administered | Sample size | Margin of error | Bob Casey Jr. (D) | Doug Mastriano (R) | Undecided |
| Franklin & Marshall College | March 27 – April 7, 2023 | 643 (RV) | ± 3.7% | 47% | 31% | 22% |
| Cygnal (R) | April 12–13, 2023 | 600 (LV) | ± 4.0% | 49% | 39% | 12% |

### Results

2024 United States Senate election in Pennsylvania :
| Party | Party | Candidate | Votes | % | ±% |
| | Republican | Dave McCormick | 3,399,295 | 48.82% | +6.20% |
| | Democratic | Bob Casey Jr. (incumbent) | 3,384,180 | 48.60% | −7.14% |
| | Libertarian | John Thomas | 89,653 | 1.29% | +0.27% |
| | Green | Leila Hazou | 66,388 | 0.95% | +0.33% |
| | Constitution | Marty Selker | 23,621 | 0.34% | N/A |
| Total votes | Total votes | Total votes | 6,963,137 | 100.0% | |
| | Republican gain from Democratic | Republican gain from Democratic | Republican gain from Democratic | Republican gain from Democratic | Republican gain from Democratic |

#### Results by county

| County | Dave McCormick Republican | Dave McCormick Republican | Bob Casey Jr. Democratic | Bob Casey Jr. Democratic | Various candidates Other parties | Various candidates Other parties | Margin | Margin | Total votes cast |
| County | # | % | # | % | # | % | # | % | Total votes cast |
| Adams | 38,505 | 63.88% | 19,947 | 33.09% | 1,824 | 3.03% | 18,556 | 30.79% | 60,276 |
| Allegheny | 272,861 | 38.112% | 425,280 | 59.404% | 17,781 | 2.484% | -152,419 | -21.290% | 715,922 |
| Armstrong | 26,653 | 72.14% | 9,136 | 24.73% | 1,155 | 3.13% | 17,517 | 47.42% | 36,944 |
| Beaver | 53,593 | 56.56% | 38,529 | 40.66% | 2,635 | 2.78% | 15,064 | 15.90% | 94,757 |
| Bedford | 22,855 | 81.50% | 4,624 | 16.49% | 564 | 2.01% | 18,231 | 65.01% | 28,043 |
| Berks | 108,058 | 53.06% | 89,063 | 45.74% | 6,521 | 3.20% | 18,995 | 9.33% | 203,642 |
| Blair | 44,741 | 69.13% | 18,445 | 28.50% | 1,537 | 2.37% | 26,296 | 40.63% | 64,723 |
| Bradford | 22,099 | 71.50% | 8,007 | 25.90% | 804 | 2.60% | 14,092 | 45.59% | 30,910 |
| Bucks | 194,203 | 48.57% | 196,444 | 49.13% | 9,186 | 2.30% | −2,241 | -0.56% | 399,833 |
| Butler | 77,328 | 63.925% | 40,973 | 33.871% | 2,666 | 2.204% | 36,355 | 30.054% | 120,967 |
| Cambria | 46,482 | 65.464% | 22,887 | 32.243% | 1,635 | 2.303% | 23,595 | 33.231% | 71,004 |
| Cameron | 1,558 | 70.37% | 580 | 26.20% | 76 | 3.43% | 978 | 44.17% | 2,214 |
| Carbon | 22,603 | 64.45% | 11,570 | 32.99% | 898 | 2.56% | 11,033 | 31.46% | 35,071 |
| Centre | 38,054 | 47.32% | 40,382 | 50.22% | 1,979 | 2.46% | -2,328 | -2.89% | 80,415 |
| Chester | 138,271 | 42.60% | 178,765 | 55.07% | 7,551 | 2.33% | -40,494 | −12.65% | 324,587 |
| Clarion | 14,179 | 72.06% | 4,683 | 23.80% | 815 | 4.14% | 9,496 | 48.26% | 19,677 |
| Clearfield | 29,063 | 72.27% | 10,111 | 25.14% | 1,038 | 2.58% | 18,952 | 47.13% | 40,212 |
| Clinton | 12,250 | 66.403% | 5,722 | 31.017% | 476 | 2.580% | 6,528 | 35.386% | 18,448 |
| Columbia | 20,617 | 63.63% | 10,969 | 33.85% | 814 | 2.51% | 9,648 | 29.78% | 32,400 |
| Crawford | 28,234 | 63.10% | 13,370 | 31.30% | 1,110 | 2.60% | 14,864 | 31.80% | 42,714 |
| Cumberland | 78,178 | 53.037% | 64,713 | 43.902% | 4,512 | 3.061% | 13,465 | 9.135% | 147,403 |
| Dauphin | 66,949 | 44.945% | 77,022 | 51.708% | 4,985 | 3.347% | −10,073 | -6.763% | 148,956 |
| Delaware | 121,482 | 37.212% | 197,424 | 60.475% | 7,551 | 2.313% | −75,942 | -23.263% | 326,457 |
| Elk | 11,939 | 69.749% | 4,679 | 28.335% | 499 | 2.916% | 7,260 | 42.414% | 17,117 |
| Erie | 65,603 | 47.94% | 67,868 | 49.60% | 3,371 | 2.46% | −2,265 | -1.66% | 136,842 |
| Fayette | 40,804 | 64.82% | 20,752 | 32.97% | 1,389 | 2.21% | 20,052 | 31.86% | 62,945 |
| Forest | 1,808 | 68.25% | 741 | 27.97% | 100 | 3.78% | 1,067 | 40.28% | 2,649 |
| Franklin | 57,217 | 68.836% | 23,591 | 28.381% | 2,313 | 2.783% | 33,626 | 40.455% | 83,121 |
| Fulton | 6,773 | 83.45% | 1,197 | 14.75% | 146 | 1.80% | 5,576 | 68.70% | 8,116 |
| Greene | 11,643 | 67.91% | 5,075 | 29.60% | 427 | 2.49% | 6,568 | 38.31% | 17,145 |
| Huntingdon | 16,910 | 74.43% | 5,582 | 24.24% | 986 | 4.28% | 11,328 | 49.19% | 23,028 |
| Indiana | 27,881 | 66.28% | 13,181 | 31.33% | 1,006 | 2.39% | 14,700 | 34.94% | 42,068 |
| Jefferson | 17,618 | 76.34% | 4,834 | 20.95% | 626 | 2.71% | 12,784 | 55.39% | 23,078 |
| Juniata | 9,252 | 76.824% | 2,478 | 20.576% | 313 | 2.600% | 6,774 | 56.248% | 12,043 |
| Lackawanna | 51,944 | 44.82% | 61,653 | 53.20% | 2,289 | 1.98% | −9,709 | −8.38% | 115,886 |
| Lancaster | 162,105 | 56.218% | 118,580 | 41.123% | 7,668 | 2.659% | 43,525 | 15.095% | 288,353 |
| Lawrence | 29,405 | 62.842% | 16,176 | 34.570% | 1,211 | 2.588% | 13,229 | 28.272% | 46,792 |
| Lebanon | 46,172 | 63.13% | 24,745 | 33.83% | 2,222 | 3.04% | 21,427 | 29.30% | 73,139 |
| Lehigh | 87,147 | 46.458% | 94,875 | 50.577% | 5,562 | 2.965% | −7,728 | −4.119% | 187,584 |
| Luzerne | 87,048 | 56.166% | 64,495 | 41.614% | 3,442 | 2.221% | 22,553 | 14.552% | 154,985 |
| Lycoming | 40,672 | 68.36% | 17,354 | 29.17% | 1,472 | 2.47% | 23,318 | 39.19% | 59,498 |
| McKean | 13,799 | 70.51% | 5,231 | 26.73% | 541 | 2 47% | 8,568 | 43.78% | 19,571 |
| Mercer | 36,468 | 62.78% | 20,302 | 34.95% | 1,318 | 2.27% | 16,166 | 27.83% | 58,088 |
| Mifflin | 16,413 | 74.79% | 4,991 | 22.74% | 542 | 2.47% | 11,422 | 52.05% | 21,946 |
| Monroe | 40,884 | 48.07% | 41,712 | 49.04% | 2,455 | 2.89% | −828 | -0.97% | 85,051 |
| Montgomery | 196,422 | 37.78% | 311,859 | 59.98% | 11,687 | 2.25% | −115,437 | −22.20% | 519,968 |
| Montour | 5,847 | 59.060% | 3,813 | 38.515% | 240 | 2.425% | 2,034 | 20.545% | 9,900 |
| Northampton | 85,787 | 49.13% | 84,762 | 48.54% | 4,066 | 2.33% | 1,025 | 0.59% | 174,615 |
| Northumberland | 28,706 | 66.305% | 13,432 | 31.025% | 1,156 | 2.670% | 15,274 | 35.280% | 43,294 |
| Perry | 18,355 | 71.476% | 6,470 | 25.195% | 855 | 3.329% | 11,885 | 46.281% | 25,680 |
| Philadelphia | 129,098 | 18.70% | 541,567 | 78.45% | 19,651 | 2.85% | −412,469 | -59.75% | 690,316 |
| Pike | 20,869 | 60.30% | 6,470 | 37.30% | 831 | 2.40% | 7,960 | 23.00% | 34,609 |
| Potter | 7,109 | 78.51% | 1,695 | 18.72% | 251 | 2.77% | 5,414 | 59.79% | 9,055 |
| Schuylkill | 48,553 | 66.66% | 22,224 | 30.51% | 2,063 | 2.83% | 26,329 | 36.15% | 72,840 |
| Snyder | 14,211 | 71.243% | 5,309 | 26.616% | 427 | 2.141% | 8.902 | 44.628% | 19,947 |
| Somerset | 30,667 | 75.135% | 9,059 | 29.195% | 1,090 | 2.671% | 21,608 | 52.940% | 40,816 |
| Sullivan | 2,612 | 70.31% | 1,021 | 27.48% | 82 | 2.21% | 1,591 | 23.83% | 3,715 |
| Susquehanna | 15,545 | 69.97% | 6,129 | 27.59% | 542 | 2.44% | 6,671 | 30.28% | 22,216 |
| Tioga | 15,778 | 73.62% | 5,066 | 23.64% | 588 | 2.74% | 10,712 | 49.98% | 21,432 |
| Union | 12,747 | 60.49% | 7,872 | 37.36% | 453 | 2.15% | 4,875 | 23.13% | 21,072 |
| Venango | 17,829 | 66.9181% | 7,872 | 29.6926% | 597 | 3.3893% | 4,875 | 18.2975% | 26,643 |
| Warren | 13,655 | 66.07% | 6,415 | 31.04% | 903 | 2.89% | 7,240 | 35.03% | 20,667 |
| Washington | 71,798 | 59.61% | 45,926 | 38.13% | 2,717 | 2.56% | 25,872 | 21.48% | 120,441 |
| Wayne | 19,331 | 65.897% | 9,385 | 31.993% | 619 | 2.110% | 9,946 | 33.904% | 29,335 |
| Westmoreland | 128,040 | 62.2816% | 45,926 | 36.3765% | 4,893 | 2.3419% | 52,036 | 24.9051% | 208,937 |
| Wyoming | 9,919 | 66.043% | 4,750 | 31.627% | 350 | 2.330% | 5,169 | 21.416% | 15,019 |
| York | 148,098 | 59.7343% | 91,779 | 37.0184% | 8,051 | 3.2473% | 56,319 | 22.7159% | 247,928 |
| Totals | 3,399,295 | 48.82% | 3,384,180 | 48.60% | 179,662 | 2.58% | 15,115 | 0.22% | 6,963,137 |
* Republican — >15%
* Republican — +12.5−15%
* Republican — +10−12.5%
* Republican — +7.5−10%
* Republican — +5−7.5%
* Republican — +2.5−5%
* Republican — +0−2.5%
* Democratic — +0−2.5%
* Democratic — +2.5−5%
* Democratic — +5−7.5%
* Democratic — +7.5-10%
* Democratic — +10−12.5%
Counties that flipped from Democratic to Republican
* Beaver (largest municipality: Aliquippa)
* Berks (largest municipality: Reading)
* Northampton (largest municipality: Bethlehem)

#### By congressional district

McCormick won 9 of 17 congressional districts, with the remaining eight going to Casey, including one that elected a Republican.
| District | Casey Jr. | McCormick | Representative |
| 1st | | | Brian Fitzpatrick |
| 2nd | | | Brendan Boyle |
| 3rd | | | Dwight Evans |
| 4th | | | Madeleine Dean |
| 5th | | | Mary Gay Scanlon |
| 6th | | | Chrissy Houlahan |
| 7th | 48% | 50% | Susan Wild (118th Congress) |
| 7th | 48% | 50% | Ryan Mackenzie (119th Congress) |
| 8th | 46% | 51% | Matt Cartwright (118th Congress) |
| 8th | 46% | 51% | Rob Bresnahan (119th Congress) |
| 9th | | | Dan Meuser |
| 10th | | | Scott Perry |
| 11th | | | Lloyd Smucker |
| 12th | | | Summer Lee |
| 13th | | | John Joyce |
| 14th | | | Guy Reschenthaler |
| 15th | | | Glenn Thompson |
| 16th | | | Mike Kelly |
| 17th | | | Chris Deluzio |

## Analysis

In Pennsylvania, a statewide recount is triggered under state law if the margin falls within 0.5% of the total vote. Preliminary results for the election reached this threshold on November 13, 2024, with McCormick at 48.9% leading Casey's 48.6%, as outstanding ballots continued to be counted across the state. Secretary of the Commonwealth Al Schmidt officially ordered the recount later that evening, with Casey declining to concede. The deadline for the counties to begin their recounts is on November 20, the third Wednesday after the election according to state law, however, counties can start their recounts as early as November 18, with all counties required to submit their results to the Department of State by noon on November 26 as the results must be reported by the Secretary of the Commonwealth by noon on November 27. Additionally, the counties must use different machines for the recount than were used on Election Day.
On Monday, November 18, following a series of challenges and disputes, the Pennsylvania Supreme Court directed all of the state's county election officials not to count certain mail-in ballots which arrived on time yet lacked a correct handwritten date on the return envelope.
The last instance of a statewide recount being held was for the 2022 Republican primary for Pennsylvania's Class 3 Senate seat, of which McCormick was also a candidate. Conversely to his stance in the 2024 general election, he unsuccessfully sued to have undated mail-in ballots counted. After completion of the recount he would concede to Mehmet Oz, with the final results expanding Oz's margin by 49 votes.

### Analysis

McCormick benefitted from the presence of former President Donald Trump on the ballot, who carried the state over Vice President Harris by just over 120,000 votes (for a margin of roughly 1.7%) in the concurrent presidential election. Indeed, McCormick cleared 60% in most counties in the state’s less-populated interior and even 70% in many.
Unlike with Ohio and Montana, however, McCormick had to seek support beyond the Trump base as he was running in a swing state. Casey and Trump both won Bucks, Erie, and Monroe Counties. McCormick campaigned with Nikki Haley in the suburbs of Pittsburgh and Philadelphia, aiming to appeal to voters uneasy about Trump by positioning himself as a more establishment candidate. Casey aired ads in late October to highlight his votes with the Trump administration, while McCormick tied Casey to Harris, highlighting his votes with the Biden administration. However, both candidates received fewer votes than their respective parties’ presidential candidate in the concurrent 2024 presidential election. Senator McCormick received about 144,000 fewer votes than President Trump, while Senator Casey received almost 39,000 fewer votes than Vice President Harris.