# 2024 United States Senate election in Montana

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vte :
The 2024 United States Senate election in Montana was held on November 5, 2024, to elect a member of the United States Senate to represent the state of Montana. Incumbent Democratic Senator Jon Tester lost re-election to a fourth term, being defeated by Republican nominee Tim Sheehy. Sheehy's victory gave Republicans control of both of Montana's Senate seats for the first time since 1911. Primary elections took place on June 4, 2024. Although Tester outperformed Kamala Harris in the concurrent presidential election by 12.8 points, which was the strongest overperformance of any Democratic Senate candidate, it was still not enough to win, as Donald Trump carried Montana by nearly 20 points. Tester received about 44,000 more votes than Kamala Harris, while Sheehy received about 32,000 fewer votes than Trump.
Despite the state's heavy partisan lean in favor of the Republican Party, Tester remained popular among his constituents. Because of this and Montana's historical inclination to ticket-split, the race was considered to be competitive. Early polling showed Tester to be leading or nearly even, but Sheehy later gained an edge. Tester was widely seen as being the most vulnerable incumbent running for re-election, due to Montana's strong Republican lean and the decline of split-ticket voting.
This race was one of two 2024 U.S. Senate races in which Democratic senators sought re-election in states where Republican Donald Trump won in both the 2016 and 2020 presidential elections, the other being Ohio. Tester's re-election was considered essential for Democrats' chances to retain the Senate majority in 2024.

## Background

Montana has generally been considered a red state at the federal executive level, voting for Republican candidates in each presidential election starting in 1996, when Bob Dole beat Bill Clinton by nearly 3 percentage points in a three-way race with Ross Perot. Since then, GOP candidates have won the White House race in the state by double digits in every race except in 2008. In the most recent presidential election, in 2020, Donald Trump beat Joe Biden in Montana by 56.92% to 40.55%. Republicans have also won all of the state's U.S. House elections since 1996. Within this time frame, Democrats have been more successful in elections for state offices and the U.S. Senate, with its governorship, state legislature, and Senate seats alternating between Democratic and Republican control. Leading up to the 2024 election, Republicans controlled both of Montana's U.S. House seats, the other U.S. Senate seat, the governorship, and had supermajority control of both houses of the state legislature.
Tester refused to endorse fellow Democrat Kamala Harris for president, a contributing factor towards the Senate race having been considered less nationalized. In 2012, the last election that featured Tester on the same ballot as the presidential election, Republican presidential candidate Mitt Romney won by 13.64%, while Tester won by 3.72% without receiving a majority (50%) of the vote.

### Top-two primary proposal

On April 4, 2023, Montana's State Senate passed a bill to institute a top-two primary system, but only for the 2024 U.S. Senate race. The bill's sponsor, Republican Greg Hertz, said it would require the winner of the 2024 Senate race to receive a majority of the vote. Incumbent Democrat Jon Tester won with a plurality of the vote in his 2006 and 2012 Senate campaigns, though he won a majority in 2018. Both Democrats and Libertarians alleged the bill was intended to prevent the Libertarian Party from placing a nominee on the general election ballot in the Senate race who could potentially pull votes away from the Republican nominee, with Democratic state senator Ryan Lynch calling it a "partisan power grab."
After the bill received backlash, Hertz introduced an amendment to make the use of a top-two primary for U.S. Senate elections permanent rather than sunsetting it after the 2024 race. The Montana House of Representatives State Administration Committee tabled the bill on April 19. An attempt to revive the bill failed, and the legislature adjourned without passing it, conclusively ending the push for a top-two primary.

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

* Jon Tester, incumbent U.S. senator (2007–2025)

#### Eliminated in primary

* Michael Hummert, retired remodeling contractor

### Endorsements

U.S. senators
* Joe Manchin, U.S. senator from West Virginia (2010–2025) (Independent; Democrat until 2024)
Statewide officials
* Andy Beshear, Governor of Kentucky (2019–present)
* Brian Schweitzer, Governor of Montana (2005–2013)
Organizations
* American Israel Public Affairs Committee (AIPAC)
* Council for a Livable World
* Democratic Majority for Israel
* End Citizens United
* Feminist Majority Foundation PAC
* Jewish Democratic Council of America
* Joint Action Committee for Political Affairs
* League of Conservation Voters
* National Organization for Women PAC
* Natural Resources Defense Council
* Peace Action
* Planned Parenthood Action Fund
* Population Connection Action Fund
* Reproductive Freedom for All
* Swing Left
Labor unions
* Association of Flight Attendants
* National Education Association

### Fundraising

Campaign finance reports as of May 15, 2024 :
| Candidate | Raised | Spent | Cash on hand |
| Jon Tester (D) | $37,330,566 | $26,017,759 | $11,793,381 |
| Source: Federal Election Commission ||||

### Results

Democratic primary results :
| Party | Party | Candidate | Votes | % |
| | Democratic | Jon Tester (incumbent) | 104,279 | 96.96% |
| | Democratic | Michael Hummert | 3,272 | 3.04% |
| Total votes | Total votes | Total votes | 107,551 | 100.00% |

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

* Tim Sheehy, founder and former CEO of Bridger Aerospace

#### Eliminated in primary

* Brad Johnson, former chair of the Montana Public Service Commission (2015–2023) and former Montana Secretary of State (2005–2009)
* Charles Walkingchild Sr., environmental contractor and candidate for Montana's 2nd congressional district in 2022

#### Withdrew

* Jeremy Mygland, construction company owner (endorsed Rosendale, ran for state senate)
* Matt Rosendale, U.S. representative from Montana's 2nd congressional district (2023–2025) and at-large district (2021–2023); nominee for U.S. Senate in 2018 (endorsed Sheehy)

#### Declined

* Greg Gianforte, governor of Montana (2021–present) (endorsed Sheehy, ran for re-election)
* Ryan Zinke, U.S. representative from Montana's 1st congressional district (2023–present) and at-large district (2015–2017); former U.S. secretary of the interior (2017–2019) (endorsed Sheehy, ran for re-election)

### Endorsements

Executive branch officials
* Donald Trump, 45th President of the United States (2017–2021)
U.S. senators
* John Barrasso, U.S. senator from Wyoming (2007–present)
* Marsha Blackburn, U.S. senator from Tennessee (2019–present)
* Ted Budd, U.S. senator from North Carolina (2023–present)
* Tom Cotton, U.S. senator from Arkansas (2015–present)
* Steve Daines, U.S. senator from Montana (2015–present)
* Bill Hagerty, U.S. senator from Tennessee (2021–present)
* Cindy Hyde-Smith, U.S. senator from Mississippi (2018–present)
* Markwayne Mullin, U.S. senator from Oklahoma (2023–present)
* Marco Rubio, U.S. senator from Florida (2011–2025)
* Eric Schmitt, U.S. senator from Missouri (2023–present)
* John Thune, U.S. senator from South Dakota (2005–present)
* Tommy Tuberville, U.S. senator from Alabama (2021–present)
Governors
* Doug Burgum, governor of North Dakota (2016–2024)
* Greg Gianforte, governor of Montana (2021–present)
* Kristi Noem, governor of South Dakota (2019–2025)
U.S. representatives
* Jim Banks, U.S. representative from Indiana's 3rd congressional district (2017–2025)
* Newt Gingrich, former speaker of the United States House of Representatives (1995−1999) from Georgia's 6th congressional district (1979−1999)
* Marjorie Taylor Greene, U.S. representative from Georgia's 14th congressional district (2021−present)
* Matt Rosendale, U.S. representative from Montana's 2nd congressional district (2021−2025)
* Ryan Zinke, U.S. representative from Montana's 1st congressional district (2023–present) and at-large district (2015–2017); former U.S. secretary of the interior (2017–2019)
Individuals
* Vivek Ramaswamy, former 2024 presidential candidate
Organizations
* Americans for Prosperity
* Gun Owners of America
* National Republican Senatorial Committee
* National Rifle Association Political Victory Fund
* Senate Conservatives Fund
* Susan B. Anthony Pro-Life America
U.S. senators
* Mike Lee, U.S. senator from Utah (2011–present)
U.S. representatives
* Matt Gaetz, U.S. representative from Florida's 1st congressional district (2017–2024)
State legislators
* Jason Ellsworth, president of the Montana Senate (2023−2025) from the 43rd district (2019–present)
* Matt Regier, speaker of the Montana House of Representatives (2023–2025) from the 4th district (2017–2025)
Individuals
* Steve Bannon, former White House chief strategist (2017) and former executive chair of Breitbart News
Organizations
* Gun Owners of America

### Fundraising

Campaign finance reports as of May 15, 2024 :
| Candidate | Raised | Spent | Cash on hand |
| Brad Johnson (R) | $42,967 | $39,697 | $3,270 |
| Tim Sheehy (R) | $10,547,437 | $8,324,164 | $2,223,272 |
| Source: Federal Election Commission ||||

### Polling

| Poll source | Date(s) administered | Sample size | Margin of error | Brad Johnson | Matt Rosendale | Tim Sheehy | Other / Undecided |
| co/efficient (R) | November 12–14, 2023 | 888 (LV) | ± 3.3% | – | 24% | 40% | 36% |
| Fabrizio, Lee & Associates (R) | October 23–25, 2023 | 600 (LV) | ± 4.0% | 6% | 35% | 38% | 21% |
| Fabrizio, Lee & Associates (R) | October 23–25, 2023 | 600 (LV) | ± 4.0% | 0% | 41% | 44% | 15% |
| J.L. Partners | August 12–17, 2023 | 418 (LV) | – | – | 52% | 21% | 28% |
| Public Policy Polling (D) | June 19–20, 2023 | 510 (LV) | ± 4.3% | – | 64% | 10% | 26% |
| Poll source | Date(s) administered | Sample size | Margin of error | Russell Fagg | Brad Johnson | Matt Rosendale | Tim Sheehy | Corey Stapleton | Ryan Zinke | Other / Undecided |
| OnMessage Inc. (R) | February 18–21, 2023 | 600 (LV) | ± 4.0% | 2% | – | 36% | 2% | 6% | 26% | 28% |

### Results

Republican primary results :
| Party | Party | Candidate | Votes | % |
| | Republican | Tim Sheehy | 139,857 | 73.60% |
| | Republican | Brad Johnson | 36,926 | 19.43% |
| | Republican | Charles Walkingchild Sr. | 13,229 | 6.96% |
| Total votes | Total votes | Total votes | 190,012 | 100.00% |

## Libertarian primary
### Candidates
#### Nominee

* Sid Daoud, Kalispell city councilor and chair of the Montana Libertarian Party

## Green primary
### Candidates
#### Withdrew after nomination

* Michael Downey, drought program coordinator

#### Replacement nominee

* Robert Barb, nominee for governor in 2020

### Results

Green primary results :
| Party | Party | Candidate | Votes | % |
| | Green | Michael Downey | 679 | 62.4% |
| | Green | Robert Barb | 410 | 37.6% |
| Total votes | Total votes | Total votes | 1,089 | 100.0% |

### Aftermath

Michael Downey, the winner of the Green Party primary election, dropped out of the race on August 12, citing the possibility that he might be a spoiler candidate in a close race. The Green Party of Montana selected the runner-up, Robert Barb, to replace Downey. The Montana Democratic Party filed a lawsuit asking for Barb to be removed from the ballot because of allegations that the Montana Green Party did not follow its procedure for designating a replacement candidate. Kathy Seeley, the district court judge hearing the case, denied the request. The Montana Democratic Party appealed to the Montana Supreme Court, but the justices refused to hear the case, leaving Barb on the ballot.

## General election
### Predictions

| Source | Ranking | As of |
| The Cook Political Report | Lean R (flip) | September 12, 2024 |
| Inside Elections | Tilt R (flip) | September 12, 2024 |
| Sabato's Crystal Ball | Lean R (flip) | September 6, 2024 |
| Decision Desk HQ/The Hill | Lean R (flip) | October 20, 2024 |
| Elections Daily | Lean R (flip) | August 9, 2024 |
| CNalysis | Tilt R (flip) | November 4, 2024 |
| RealClearPolitics | Lean R (flip) | September 12, 2024 |
| Split Ticket | Lean R (flip) | October 23, 2024 |

### Post-primary endorsements

U.S. representatives
* Tulsi Gabbard, U.S. representative from Hawaii's 2nd congressional district (2013–2021)
U.S. senators
* John Thune, Senate Minority Whip (2021–present) from South Dakota (2005–2025)
Statewide officials
* Ron DeSantis, Governor of Florida
Individuals
* Charlie Kirk, founder of Turning Point USA
Organizations
* National Rifle Association Political Victory Fund
Statewide officials
* Bob Brown, former Montana Secretary of State (2001–2005) (Republican)
* Marc Racicot, former Governor of Montana (1993–2001) (Republican)
* Gretchen Whitmer, Governor of Michigan (2019–present)
State senators
* Terry Vermeire, state senator from the 39th district (2023–present) (Republican)
State representatives
* Mallerie Stromswold, former state representative from the 50th district (2021–2023) (Republican)
* Dan Hurwitz, former state representative from the 83rd district (2003–2005) (Republican)
Individuals
* Harry Dunn, former U.S. Capitol Police officer
Organizations
* National Committee to Preserve Social Security and Medicare

### Fundraising

In October 2024, total spending for both sides (including both campaign spending and Independent expenditures), was on track to exceed $315 million. With Montana having only 648,000 active registered voters, the amount spent averaged $487 per voter, making the race the most expensive congressional campaign in U.S. history on a per voter basis. Democrats outspent Republicans by $50 million. Most of the money came from out-of-state dark money groups.
Campaign finance reports as of October 16, 2024 :
| Candidate | Raised | Spent | Cash on hand |
| Jon Tester (D) | $88,163,151 | $84,499,372 | $4,144,352 |
| Tim Sheehy (R) | $26,161,679 | $22,284,629 | $3,877,050 |
| Source: Federal Election Commission ||||

### Debates

| Dates | Host | Tester | Sheehy | Link |
| June 10, 2024 | Montana Broadcasters Association | Participant | Participant | YouTube |
| September 30, 2024 | Montana PBS | Participant | Participant | YouTube |

### Polling

Aggregate polls
| Source of poll aggregation | Dates administered | Dates updated | Tim Sheehy (R) | Jon Tester (D) | Undecided | Margin |
| RealClearPolitics | October 5 – November 4, 2024 | November 4, 2024 | 50.7% | 43.0% | 6.3% | Sheehy +7.7 |
| 538 | through November 4, 2024 | November 4, 2024 | 49.7% | 42.7% | 7.6% | Sheehy +7.0% |
| 270toWin | October 10–27, 2024 | November 4, 2024 | 51.0% | 45.0% | 4.0% | Sheehy +6.0% |
| TheHill/DDHQ | through November 4, 2024 | November 4, 2024 | 50.0% | 43.1% | 6.9% | Sheehy +6.9% |
| Average | Average | Average | 50.4% | 43.5% | 6.1% | Sheehy +6.9% |
| Poll source | Date(s) administered | Sample size | Margin of error | Jon Tester (D) | Tim Sheehy (R) | Other | Undecided |
| AtlasIntel | November 3–4, 2024 | 752 (LV) | ± 4.0% | 39% | 50% | 5% | 6% |
| Emerson College | October 23–25, 2024 | 1,000 (LV) | ± 3.0% | 48% | 51% | 2% | – |
| Emerson College | October 23–25, 2024 | 1,000 (LV) | ± 3.0% | 46% | 50% | 2% | 3% |
| MSU Billings | September 30 – October 16, 2024 | 760 (LV) | ± 3.6% | 43% | 43% | 6% | 8% |
| New York Times/Siena College | October 5–8, 2024 | 656 (LV) | ± 4.3% | 44% | 52% | – | 4% |
| New York Times/Siena College | October 5–8, 2024 | 656 (RV) | ± 4.3% | 44% | 51% | – | 4% |
| Public Opinion Strategies (R) | September 29 – October 1, 2024 | 500 (LV) | ± 4.3% | 45% | 51% | 2% | 2% |
| Remington Research Group (R) | September 16–20, 2024 | 800 (LV) | ± 3.5% | 44% | 52% | – | 4% |
| RMG Research | September 12–19, 2024 | 491 (LV) | ± 4.4% | 43% | 50% | 2% | 4% |
| Fabrizio Ward (R)/ David Binder Research (D) | August 25–29, 2024 | 600 (LV) | ± 4.0% | 45% | 51% | – | 4% |
| Fabrizio Ward (R)/ David Binder Research (D) | August 25–29, 2024 | 600 (LV) | ± 4.0% | 41% | 49% | 5% | 5% |
| Public Opinion Strategies (R) | August 18–20, 2024 | 500 (LV) | ± 4.4% | 44% | 51% | 3% | 2% |
| Rasmussen Reports (R) | August 13–20, 2024 | 835 (LV) | ± 3.0% | 43% | 50% | – | 7% |
| RMG Research | August 6–14, 2024 | 540 (RV) | ± 4.2% | 49% | 44% | 2% | 4% |
| American Pulse Research & Polling | August 10–12, 2024 | 538 (RV) | ± 4.2% | 45% | 51% | – | 4% |
| Emerson College | August 5–6, 2024 | 1,000 (LV) | ± 3.0% | 46% | 48% | – | 5% |
| Expedition Strategies | June 24 – July 8, 2024 | 251 (LV) | – | 47% | 48% | – | 4% |
| Remington Research Group (R) | June 29 – July 1, 2024 | 570 (LV) | ± 4.0% | 45% | 50% | – | 5% |
| Torchlight Strategies (R) | June 22–26, 2024 | 649 (RV) | ± 3.9% | 41% | 47% | 5% | 7% |
| Public Opinion Strategies (R) | June 11–13, 2024 | 500 (LV) | ± 4.4% | 46% | 46% | 4% | 4% |
| Fabrizio, Lee & Associates (R) | June 3–5, 2024 | 500 (LV) | ± 4.4% | 48% | 48% | – | 4% |
| Fabrizio, Lee & Associates (R) | June 3–5, 2024 | 500 (LV) | ± 4.4% | 43% | 46% | 4% | 7% |
| J.L. Partners | March 26–29, 2024 | 503 (LV) | ± 4.3% | 45% | 48% | – | 7% |
| Emerson College | February 26 – March 2, 2024 | 1,000 (RV) | ± 3.0% | 44% | 42% | – | 14% |
| SurveyUSA | February 12–15, 2024 | 549 (LV) | ± 4.5% | 49% | 40% | 3% | 7% |
| Emerson College | October 1–4, 2023 | 447 (RV) | ± 4.6% | 39% | 35% | 6% | 21% |
| J.L. Partners | August 12–17, 2023 | 741 (LV) | – | 42% | 46% | – | 12% |
Jon Tester vs. Greg Gianforte
| Poll source | Date(s) administered | Sample size | Margin of error | Jon Tester (D) | Greg Gianforte (R) | Undecided |
| Political Company (R) | January 30 – February 1, 2023 | 534 (LV) | ± 4.0% | 45% | 45% | 10% |
Jon Tester vs. Brad Johnson
| Poll source | Date(s) administered | Sample size | Margin of error | Jon Tester (D) | Brad Johnson (R) | Other | Undecided |
| SurveyUSA | February 12–15, 2024 | 549 (LV) | ± 4.5% | 50% | 35% | 4% | 11% |
Jon Tester vs. Matt Rosendale
| Poll source | Date(s) administered | Sample size | Margin of error | Jon Tester (D) | Matt Rosendale (R) | Other | Undecided |
| SurveyUSA | February 12–15, 2024 | 549 (LV) | ± 4.5% | 49% | 40% | 4% | 7% |
| J.L. Partners | August 12–17, 2023 | 741 (LV) | – | 43% | 46% | – | 11% |
| OnMessage Inc. (R) | February 18–21, 2023 | 600 (LV) | ± 4.0% | 41% | 46% | 5% | 7% |
| Political Company (R) | January 30 – February 1, 2023 | 534 (LV) | ± 4.0% | 45% | 40% | – | 15% |
Jon Tester vs. Ryan Zinke
| Poll source | Date(s) administered | Sample size | Margin of error | Jon Tester (D) | Ryan Zinke (R) | Undecided |
| Political Company (R) | January 30 – February 1, 2023 | 534 (LV) | ± 4.0% | 46% | 40% | 14% |

### Results

2024 United States Senate election in Montana :
| Party | Party | Candidate | Votes | % | ±% |
| | Republican | Tim Sheehy | 319,682 | 52.64% | +5.86% |
| | Democratic | Jon Tester (incumbent) | 276,305 | 45.50% | −4.83% |
| | Libertarian | Sid Daoud | 7,272 | 1.20% | −1.68% |
| | Green | Robert Barb | 4,003 | 0.66% | N/A |
| Total votes | Total votes | Total votes | 607,262 | 100.00% | N/A |
| | Republican gain from Democratic | Republican gain from Democratic | Republican gain from Democratic | Republican gain from Democratic | Republican gain from Democratic |

#### By county

From Secretary of State of Montana
| County | Tim Sheehy Republican | Tim Sheehy Republican | Jon Tester Democratic | Jon Tester Democratic | Sid Daoud Libertarian | Sid Daoud Libertarian | Robert Barb Green | Robert Barb Green | Total Votes |
| County | # | % | # | % | # | % | # | % | Total Votes |
| Beaverhead | 3,707 | 63.45% | 2,024 | 34.65% | 67 | 1.15% | 43 | 0.74% | 5,841 |
| Big Horn | 1,580 | 35.48% | 2,805 | 62.99% | 42 | 0.94% | 26 | 0.58% | 4,453 |
| Blaine | 1,192 | 38.99% | 1,814 | 59.34% | 29 | 0.95% | 22 | 0.72% | 3,057 |
| Broadwater | 3,503 | 72.35% | 1,219 | 25.18% | 82 | 1.69% | 38 | 0.78% | 4,842 |
| Carbon | 4,459 | 60.35% | 2,794 | 37.82% | 95 | 1.29% | 40 | 0.54% | 7,388 |
| Carter | 732 | 85.71% | 109 | 12.76% | 7 | 0.82% | 6 | 0.70% | 854 |
| Cascade | 19,808 | 52.30% | 17,323 | 45.73% | 462 | 1.22% | 284 | 0.75% | 37,877 |
| Chouteau | 1,643 | 55.49% | 1,274 | 43.03% | 25 | 0.84% | 19 | 0.64% | 2,961 |
| Custer | 3,818 | 65.60% | 1,855 | 31.87% | 81 | 1.39% | 66 | 1.13% | 5,820 |
| Daniels | 719 | 75.37% | 220 | 23.06% | 8 | 0.84% | 7 | 0.73% | 954 |
| Dawson | 3,269 | 70.26% | 1,259 | 27.06% | 69 | 1.48% | 56 | 1.20% | 4,653 |
| Deer Lodge | 1,820 | 37.07% | 2,991 | 60.92% | 62 | 1.26% | 37 | 0.75% | 4,910 |
| Fallon | 1,200 | 80.27% | 256 | 17.12% | 30 | 2.01% | 9 | 0.60% | 1,495 |
| Fergus | 4,749 | 70.22% | 1,910 | 28.24% | 63 | 0.93% | 41 | 0.61% | 6,763 |
| Flathead | 38,582 | 60.72% | 23,647 | 37.21% | 974 | 1.53% | 339 | 0.53% | 63,542 |
| Gallatin | 30,537 | 43.28% | 39,094 | 55.41% | 646 | 0.92% | 278 | 0.39% | 70,555 |
| Garfield | 720 | 90.45% | 68 | 8.54% | 5 | 0.63% | 5 | 0.63% | 796 |
| Glacier | 1,426 | 27.78% | 3,638 | 70.86% | 40 | 0.78% | 30 | 0.58% | 5,134 |
| Golden Valley | 422 | 81.15% | 91 | 17.50% | 5 | 0.96% | 2 | 0.38% | 520 |
| Granite | 1,377 | 63.02% | 778 | 35.60% | 19 | 0.87% | 11 | 0.50% | 2,185 |
| Hill | 3,217 | 47.09% | 3,438 | 50.32% | 109 | 1.60% | 68 | 1.00% | 6,832 |
| Jefferson | 5,108 | 61.15% | 3,099 | 37.10% | 97 | 1.16% | 49 | 0.59% | 8,353 |
| Judith Basin | 991 | 72.87% | 352 | 25.88% | 12 | 0.88% | 5 | 0.37% | 1,360 |
| Lake | 8,881 | 52.26% | 7,798 | 45.89% | 200 | 1.18% | 114 | 0.67% | 16,993 |
| Lewis and Clark | 19,367 | 45.69% | 22,175 | 52.31% | 527 | 1.24% | 320 | 0.75% | 42,389 |
| Liberty | 683 | 68.16% | 307 | 30.64% | 7 | 0.70% | 5 | 0.50% | 1,002 |
| Lincoln | 8,291 | 70.15% | 3,287 | 27.81% | 160 | 1.35% | 81 | 0.69% | 11,819 |
| Madison | 4,388 | 67.36% | 2,025 | 31.09% | 69 | 1.06% | 32 | 0.49% | 6,514 |
| McCone | 890 | 82.03% | 173 | 15.94% | 13 | 1.20% | 9 | 0.83% | 1,085 |
| Meagher | 845 | 71.61% | 309 | 26.19% | 16 | 1.36% | 10 | 0.85% | 1,180 |
| Mineral | 1,831 | 64.27% | 950 | 33.35% | 45 | 1.58% | 23 | 0.81% | 2,849 |
| Missoula | 23,743 | 32.36% | 48,429 | 66.00% | 751 | 1.02% | 449 | 0.61% | 73,372 |
| Musselshell | 2,408 | 80.13% | 536 | 17.84% | 43 | 1.43% | 18 | 0.60% | 3,005 |
| Park | 5,614 | 47.51% | 6,009 | 50.85% | 133 | 1.13% | 60 | 0.51% | 11,816 |
| Petroleum | 274 | 83.54% | 50 | 15.24% | 4 | 1.22% | 0 | 0.00% | 328 |
| Phillips | 1,678 | 76.27% | 490 | 22.27% | 17 | 0.77% | 15 | 0.68% | 2,200 |
| Pondera | 1,804 | 62.94% | 1,017 | 35.48% | 25 | 0.87% | 20 | 0.70% | 2,866 |
| Powder River | 886 | 79.82% | 205 | 18.45% | 16 | 1.44% | 3 | 0.27% | 1,110 |
| Powell | 2,160 | 65.43% | 1,065 | 32.26% | 50 | 1.51% | 26 | 0.79% | 3,301 |
| Prairie | 489 | 70.56% | 180 | 25.97% | 14 | 2.02% | 10 | 1.44% | 693 |
| Ravalli | 19,116 | 63.62% | 10,449 | 34.78% | 322 | 1.07% | 160 | 0.53% | 30,047 |
| Richland | 3,914 | 73.85% | 1,238 | 23.36% | 89 | 1.68% | 59 | 1.11% | 5,300 |
| Roosevelt | 1,636 | 41.33% | 2,249 | 56.82% | 36 | 0.91% | 37 | 0.93% | 3,958 |
| Rosebud | 2,208 | 59.29% | 1,435 | 38.53% | 49 | 1.32% | 32 | 0.86% | 3,724 |
| Sanders | 5,663 | 69.86% | 2,241 | 27.65% | 121 | 1.49% | 81 | 1.00% | 8,106 |
| Sheridan | 1,159 | 61.10% | 685 | 36.11% | 28 | 1.48% | 25 | 1.32% | 1,897 |
| Silver Bow | 6,232 | 33.84% | 11,854 | 64.36% | 191 | 1.0% | 141 | 0.77% | 18,418 |
| Stillwater | 4,473 | 75.40% | 1,352 | 22.79% | 65 | 1.10% | 42 | 0.71% | 5,932 |
| Sweet Grass | 1,685 | 70.15% | 665 | 27.69% | 33 | 1.37% | 19 | 0.79% | 2,402 |
| Teton | 2,323 | 64.42% | 1,216 | 33.72% | 43 | 1.19% | 24 | 0.67% | 3,606 |
| Toole | 1,436 | 70.25% | 558 | 27.30% | 29 | 1.42% | 21 | 1.03% | 2,044 |
| Treasure | 336 | 75.17% | 101 | 22.60% | 8 | 1.79% | 2 | 0.45% | 447 |
| Valley | 2,672 | 65.28% | 1,307 | 31.93% | 67 | 1.64% | 47 | 1.14% | 4,093 |
| Wheatland | 792 | 72.93% | 278 | 25.60% | 10 | 0.92% | 6 | 0.55% | 1,086 |
| Wibaux | 414 | 75.27% | 121 | 22.00% | 11 | 2.00% | 4 | 0.73% | 550 |
| Yellowstone | 46,812 | 57.10% | 33,493 | 40.85% | 1,051 | 1.28% | 629 | 0.77% | 81,985 |
* 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%
* Democratic — +12.5−15%  Democratic—+>15%
Counties that flipped from Democratic to Republican
* Cascade (largest city: Great Falls)
* Lake (largest city: Polson)

#### By congressional district

Sheehy and Tester each won one of two congressional districts, with Tester narrowly winning the 1st district, which elected a Republican representative.
| District | Tester | Sheehy | Representative |
| 1st | 50% | 49% | Ryan Zinke |
| 2nd | 41% | 57% | Matt Rosendale (118th Congress) |
| 2nd | 41% | 57% | Troy Downing (119th Congress) |