Karishma Manzur made a splash when she announced a challenge from the left for Democrat Pappas, who has represented New Hampshire in Washington since 2018. On her website Manzur proclaims, "As the first female PhD scientist ever elected to the U.S. Senate, Karishma will bring scientific leadership to strengthen our economy, protect public health, and keep America at the forefront of medical research." 

Chris Pappas has served as a U.S. Representative since 2018 and previously served on New Hampshire’s Executive Council. (His family is also known for their world-famous chicken tenders at the Puritan Backroom Restaurant in Manchester.) In Congress, Pappas has positioned himself as a moderate, occasionally breaking with his party on high-profile votes such as the Laken Riley Act and the Middle Class Borrower Protection Act. In 2024, Pappas won reelection to the U.S. House. He is now seeking to move up to the U.S. Senate in 2026.

Jared Sullivan is a current state representative from the North Country. When asked on WMUR why he chose to challenge Chris Pappas, Rep. Sullivan said, "I'm trying to give an alternative, somebody who actually is willing to stand up and fight and use their voice. And I don't think he's done that." 

Scott Brown, a former U.S. Senator from Massachusetts and U.S. Ambassador to New Zealand, is mounting a political comeback in New Hampshire. “I’m running for the United States Senate to restore common sense, keep our border secure, and fight for our New Hampshire values,” Brown said. He previously ran for Senate in New Hampshire in 2014 but lost to Jeanne Shaheen.

Dan Innis is a three-term Republican state senator from Bradford, a former UNH professor and dean, and the owner of Trails End Farm. He previously ran in the 2014 and 2016 GOP primaries for New Hampshire’s 1st Congressional District. Announcing his 2026 Senate bid, Innis said, "People need information to make good decisions, and they need to pick the candidate that's going to deliver the most value to them. That candidate is me." 

Sen. Innis dropped out of the race in September 2025 and threw his support behind John E. Sununu - a candidate who has yet to enter the race.

John E. Sununu, a former Republican U.S. Senator and three-term congressman, hopes to win back the Senate seat he once held. First elected to the Senate in 2002 after defeating then-Gov. Jeanne Shaheen, he later lost to her in their 2008 rematch. In launching his 2026 campaign, Sununu said Congress has become “loud, dysfunctional, even angry,” and that he wants to “help calm the waters.” After nearly two decades in the private sector, Sununu is emphasizing civility, fiscal discipline, and practical problem-solving as he seeks to re-enter public service.