New Hampshire’s Senate seat is open because Sen. Jeanne Shaheen (D) chose not to seek a fourth term. The general election was set on September 8, when Rep. Chris Pappas won the Democratic nomination and former Sen. John E. Sununu beat former Massachusetts Sen. Scott Brown for the Republican nod, by about 70% to 25% in early returns.
It is one of only two Democratic-held seats that forecasters rated as competitive this fall, which makes it central to the Senate math. Cook Political Report now rates it Lean Democrat, after moving it to Toss-Up in September and back on October 6.
- Open seat: Sen. Jeanne Shaheen (D) is retiring; she endorsed Pappas in April 2025.
- Chris Pappas (D) has represented NH-01 since 2019. John E. Sununu (R) held this Senate seat from 2003 until Shaheen defeated him in 2008.
- Cook moved the race from Lean D to Toss-Up on Sept. 15, then to Lean D on Oct. 6.
- The first post-primary polls had Pappas ahead: UNH 50–42 (Sept. 17–21, likely voters) and Trafalgar 47–41.
- New Hampshire has no early voting; absentee voting requires a qualifying reason, and absentee ballots must arrive by 5 p.m. on Election Day.
The candidates
Chris Pappas (D)
U.S. Rep., NH-01Represents New Hampshire’s 1st Congressional District, first elected in 2018. Shaheen endorsed him early, and he won the September 8 Democratic primary easily. His House seat is open this year.
John E. Sununu (R)
Former U.S. senatorServed one Senate term, 2003–2009, before losing this seat to Shaheen in 2008. He is the brother of former Gov. Chris Sununu and has President Trump’s endorsement.
The matchup is unusual: a former senator trying to win back the same seat he lost 18 years ago, against a four-term congressman who has never run statewide.
How the ratings have moved
- Sept. 10 · Inside ElectionsMoved the race to Toss-Up after Sununu’s strong primary showing became clear.
- Sept. 15 · Cook Political ReportLean D to Toss-Up.
- Oct. 6 · Cook Political ReportToss-Up back to Lean D, in the same update that moved Kansas to Toss-Up and North Carolina to Likely D. Newsweek reported that Cook warned the race “could still end up being closer than it should be.”
Sabato’s Crystal Ball has rated the race Leans Democratic. As always, ratings are judgments about probability, not predictions of the result.
What the polls show
| Pollster | Dates / sample | Pappas | Sununu |
|---|---|---|---|
| University of New Hampshire | Sept. 17–21 · 1,418 LV | 50 | 42 |
| Trafalgar | Sept. · 1,082 LV | 47 | 41 |
Before the primary, the picture was mixed: a Saint Anselm poll in mid-August had Pappas ahead 48–41, while UNH’s August 20–24 survey had Sununu up 45–43. The shift since then is one reason Cook moved the race back toward Democrats.
New Hampshire has a large bloc of undeclared voters and a history of swinging. Harris carried the state in 2024, but Republicans hold the governorship: Gov. Kelly Ayotte (R) is seeking re-election against former Executive Councilor Cinde Warmington (D), a race Cook rates Likely R. Ticket-splitting between those two races is one of the things to watch on election night.
Why the seat matters for Senate control
Democrats hold 47 seats, counting two independents who caucus with them, and need a net gain of four for a majority. Every Democratic-held seat they lose adds another Republican seat they must flip. That makes New Hampshire, along with Michigan, the core of the Democrats’ defensive map, and a natural target for Republicans hoping to offset losses elsewhere. Our Senate Toss-Up rundown walks through the arithmetic, and our September primaries recap covers how this matchup was set.
How voting works in New Hampshire
- Registration: New Hampshire allows registration at the polls on Election Day with proof of identity, age, citizenship and domicile. Each town’s supervisors of the checklist also hold a final pre-election session between Oct. 21 and Oct. 28.
- No early voting: New Hampshire does not offer in-person early voting. Absentee voting requires a qualifying reason, such as being away on Election Day or a disability.
- Absentee deadline: absentee ballots must be received by 5 p.m. on Election Day, according to NCSL.
- Poll hours are set locally within state limits; check with your town or city clerk. Our poll closing times guide covers results-night timing.
Debates
Any scheduled Pappas–Sununu debates will be listed in our Senate debate tracker, which we update through Election Day.
Frequently asked questions
Who is running for Senate in New Hampshire in 2026?
Rep. Chris Pappas (D) and former Sen. John E. Sununu (R) are the major-party nominees for the seat held by retiring Sen. Jeanne Shaheen (D).
Has John E. Sununu been a senator before?
Yes. He represented New Hampshire in the U.S. Senate from 2003 to 2009 and lost this seat to Jeanne Shaheen in 2008. He is the brother of former Gov. Chris Sununu.
What is the Cook rating for the New Hampshire Senate race?
Lean Democrat as of Oct. 6, 2026. Cook had moved it to Toss-Up on Sept. 15 before shifting it back.
Does New Hampshire have early voting?
No. New Hampshire does not offer in-person early voting, and absentee voting requires a qualifying reason. Absentee ballots must be received by 5 p.m. on Election Day.
Can I register to vote on Election Day in New Hampshire?
Yes. New Hampshire allows registration at the polling place on Election Day with proof of identity, age, citizenship and domicile.
New Hampshire is the Republicans’ best chance to take a Democratic seat on Cook’s current board, and the early-autumn polling has favored Pappas. The state’s independent streak and its split-ticket history are why nobody treats a September lead as settled.
Sources
- Cook Political Report: A Senate majority is squarely in Democrats’ sights as Kansas moves to Toss Up; two other races shift left (Oct. 6, 2026)
- Newsweek: Three Senate races shift toward Democrats with midterms four weeks away
- New Hampshire Secretary of State: Registering to vote
- NCSL: Table 11, Receipt and postmark deadlines for absentee/mail ballots