The 2018 United States Senate election in Montana was held on November 6, 2018, to elect a member of the

United States Senate The United States Senate is a chamber of the Bicameralism, bicameral United States Congress; it is the upper house, with the United States House of Representatives, U.S. House of Representatives being the lower house. Together, the Senate and ...

to represent the

State of Montana Montana ( ) is a landlocked state in the Mountain West subregion of the Western United States. It is bordered by Idaho to the west, North Dakota to the east, South Dakota to the southeast, Wyoming to the south, and the Canadian provinces of ...

, concurrently with other elections to the United States Senate,

elections An election is a formal group decision-making process whereby a population chooses an individual or multiple individuals to hold public office. Elections have been the usual mechanism by which modern representative democracy has operated ...

to the

United States House of Representatives The United States House of Representatives is a chamber of the Bicameralism, bicameral United States Congress; it is the lower house, with the U.S. Senate being the upper house. Together, the House and Senate have the authority under Artic ...

and various state and local elections. This was one of ten Democratic-held Senate seats up for election in a state that

Donald Trump Donald John Trump (born June 14, 1946) is an American politician, media personality, and businessman who is the 47th president of the United States. A member of the Republican Party (United States), Republican Party, he served as the 45 ...

won in the 2016 presidential election. Incumbent Democratic Senator

Jon Tester Raymond Jon Tester (born August 21, 1956) is an American politician and farmer who served from 2007 to 2025 as a United States Senate, United States senator from Montana and from 2005 to 2007 as president of the Montana Senate. A member of the ...

was reelected to a third term, defeating Republican

State Auditor State auditors (also known as state comptrollers, state controllers, or state examiners, among others) are fiscal officers lodged in the executive or legislative branches of U.S. state governments who serve as external auditors, program eval ...

Matt Rosendale Matthew Martin Rosendale Sr. (born July 7, 1960) is an American politician and former real estate developer who represented Montana in the United States House of Representatives from 2021 to 2025. A member of the Republican Party, Rosendale ser ...

. Rosendale conceded on November 7, 2018. This was the first Senate election in which Tester received a majority of votes. As of 2025, this is the last time Democrats won a congressional and/or statewide election in Montana. Following his loss, Rosendale went on to run for Montana's vacant congressional seat in 2020 and won, taking office in the U.S. House of Representatives in January 2021.

Democratic primary

Candidates

Nominated

, incumbent U.S. senator

Endorsements

Results

Republican primary

Candidates

Nominated

, auditor of Montana and candidate for Congress in

2014 The year 2014 was marked by the surge of the Western African Ebola epidemic, West African Ebola epidemic, which began in 2013, becoming the List of Ebola outbreaks, most widespread outbreak of the Ebola, Ebola virus in human history, resul ...

Eliminated in primary

Troy Downing Troy Bryan Downing (born March 4, 1967) is an American politician and businessman serving as a member of the U.S. House of Representatives for since 2025. A member of the Republican Party, he previously held the office of Montana state auditor ...

, veteran and businessman * Russell Fagg, former

Yellowstone County Yellowstone County is the most populous county in the U.S. state of Montana. As of the 2020 census, the population was 164,731. Its county seat is Billings, the state's most populous city. Like the nearby national park, Yellowstone County ...

District Judge * Albert Olszewski, state senator and candidate for lieutenant governor in

2012 2012 was designated as: *International Year of Cooperatives *International Year of Sustainable Energy for All Events January *January 4 – The Cicada 3301 internet hunt begins. * January 12 – Peaceful protests begin in the R ...

Withdrew

* Ron Murray, businessman and candidate for the state house in 2010

Declined

* Tim Fox,

Attorney General of Montana The Montana Department of Justice is a state law enforcement agency of Montana. The Department is equivalent to the State Bureau of Investigation in other states. The Montana Attorney General, currently Republican Austin Knudsen, heads the age ...

* Robert J. O'Neill, former

Navy SEAL The United States Navy Sea, Air, and Land (SEAL) Teams, commonly known as Navy SEALs, are the United States Navy's primary special operations force and a component of the United States Naval Special Warfare Command. Among the SEALs' main funct ...

(''endorsed Troy Downing'') *

Marc Racicot Marc Racicot (; born July 24, 1948) is an American attorney, lobbyist, and former Republican politician who served as the 21st governor of Montana from 1993 until 2001. After leaving office, Racicot worked as a lobbyist for the law firm Bracewe ...

, former governor and former chairman of the

Republican National Committee The Republican National Committee (RNC) is the primary committee of the Republican Party of the United States. Its members are chosen by the state delegations at the national convention every four years. It is responsible for developing and pr ...

(''endorsed Russell Fagg'') * Corey Stapleton,

Secretary of State of Montana The secretary of state of Montana is one of the elected constitutional officers of executive branch of the U.S. state of Montana. The current secretary of state is Christi Jacobsen. Organization The Secretary of State's Office is composed of fi ...

, candidate for governor in

and candidate for Congress in

Ryan Zinke Ryan Keith Zinke ( ; born November 1, 1961) is an American politician and businessman serving as the U.S. representative for since 2023. A member of the Republican Party, Zinke served in the Montana Senate from 2009 to 2013 and as the U.S. re ...

, former

Secretary of the Interior Secretary of the Interior may refer to: * Secretary of the Interior (Mexico) * Interior Secretary of Pakistan * Secretary of the Interior and Local Government (Philippines) * United States Secretary of the Interior See also

*Interior ministry ...

and former U.S. representative

Endorsements

Polling

Results

Libertarian primary

Candidates

Nominated

* Rick Breckenridge, 2016 candidate for the U.S. House of Representatives In October 2018, Breckenridge told a reporter from the

Associated Press The Associated Press (AP) is an American not-for-profit organization, not-for-profit news agency headquartered in New York City. Founded in 1846, it operates as a cooperative, unincorporated association, and produces news reports that are dist ...

that he opposed the use of

dark money In politics, particularly the politics of the United States, dark money refers to spending to influence elections, public policy, and political discourse, where the source of the money is not disclosed to the public. In the United States, ...

in politics. Breckenridge said that he realistically anticipated only receiving three or four percent of the vote in the general election, and that he endorsed Rosendale's efforts to stop the use of dark money in politics. The Associated Press interpreted Breckenridge's comments as a statement that Breckenridge was dropping out of the race and endorsing Rosendale. Breckenridge later stated that his use of the word "endorse" referred only to stopping the use of dark money in politics, and said he was still running for the Senate.

Green Party

Kelly won the Green Party nomination, but a Montana district court judge ruled that he had insufficient signatures to get on the ballot.

Candidates

Nominee (removed from ballot)

* Steve Kelly, artist and environmental activist

Eliminated in primary

* Timothy Adams

Results

General election

Debates

Complete video of debate

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September 29, 2018
Complete video of debate

YouTube YouTube is an American social media and online video sharing platform owned by Google. YouTube was founded on February 14, 2005, by Steve Chen, Chad Hurley, and Jawed Karim who were three former employees of PayPal. Headquartered in ...

October 14, 2018

Predictions

Endorsements

Fundraising

Polling

Results

2018 Montana Senate election results map by state senate district

By county

From

Counties that flipped from Democratic to Republican * Chouteau (largest municipality: Fort Benton) * Rosebud (largest municipality: Colstrip) *

Yellowstone Yellowstone National Park is a List of national parks of the United States, national park of the United States located in the northwest corner of Wyoming, with small portions extending into Montana and Idaho. It was established by the 42nd U ...

(largest municipality:

Billings Billings is the most populous city in the U.S. state of Montana, with a population of 117,116 as of the 2020 census. Located in the south-central portion of the state, it is the seat of Yellowstone County and the principal city of the Billin ...

)

References

External links

Candidates
at

Vote Smart Vote Smart, formerly called Project Vote Smart, is an American non-profit, non-partisan research organization that collects and distributes information on candidates for public office in the United States. It covers candidates and elected offic ...

Candidates
at

Ballotpedia Ballotpedia is a nonprofit and nonpartisan online political encyclopedia that covers federal, state, and local politics, elections, and public policy in the United States. The website was founded in 2007. Ballotpedia is sponsored by the Lucy Bur ...

Campaign finance
at FEC
Campaign finance
at

OpenSecrets OpenSecrets is a nonprofit organization based in Washington, D.C., that tracks and publishes data on campaign finance and lobbying, including a revolving door database which documents the individuals who have worked in both the public sector an ...

Official campaign websites
Matt Rosendale (R) for SenateJon Tester (D) for Senate
{{2018 United States elections

2018 Events January * January 1 – Bulgaria takes over the Presidency of the Council of the European Union, after the Estonian presidency. * January 4 – SPLM-IO rebels loyal to Chan Garang Lual start a raid against Juba, capital of ...

Montana Montana ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Idaho to the west, North Dakota to the east, South Dakota to the southeast, Wyoming to the south, an ...