New Hampshire’s open 2026 U.S. Senate race continues to take shape as one of the most closely watched contests on the national map, and the latest survey from the University of New Hampshire Survey Center gives both parties a clear picture of where their primary fields and general election numbers stand entering the summer. According to the UNH Survey Center’s April 23 release, First District Congressman Chris Pappas is comfortably ahead in the Democratic primary, former Senator John Sununu has consolidated his Republican primary lead over former Massachusetts Senator Scott Brown, and Pappas holds an edge of seven percentage points over Sununu in a head-to-head general election test.

The Senate seat opened up after longtime Democratic Sen. Jeanne Shaheen announced she would not seek a fourth term. Shaheen’s retirement turned a reliably contested but Democratic-leaning seat into a true national tossup, drawing national investment from both parties and helping to fuel an unusually crowded early primary picture on both sides.

The Numbers in Plain Terms

In the Democratic primary, 61 percent of likely primary voters said they would back Pappas, the four-term congressman whose Manchester-area district has reshaped him into one of the more visible Democratic operators in New England. Eighteen percent said they would vote for Karishma Manzur, a scientist who entered the race in early winter and has been running well to the activist left of Pappas on climate, drug pricing and labor issues. Two percent of voters were split between Rep. Jared Sullivan, a state representative who has been mounting a long-shot primary challenge from the more populist progressive wing of the party, and write-in votes. Eighteen percent remained undecided.

The Republican primary picture is dominated by Sununu, who in this April survey sat at 56 percent. Sununu had been at 48 percent in January’s UNH polling, and the eight-point gain reflects a quieter Brown campaign and the slow consolidation behind Sununu by Republican county committees and several prominent former Ayotte and Sununu administration officials. Brown, the former senator from Massachusetts who moved to New Hampshire and lost a 2014 Senate bid here, sat at 19 percent. A roughly 25 percent slice of the Republican electorate remains undecided, suggesting Brown still has runway if his campaign can convert summer field operations into name recognition gains.

In a head-to-head general election test, Pappas led Sununu 49 to 42, with 4 percent backing another candidate and 6 percent undecided. That seven-point spread is one of the wider Pappas leads the UNH Survey Center has measured this cycle. In Emerson College’s parallel work, the same matchup has registered closer, sometimes within a single point. RealClearPolling, which averages multiple surveys, has continued to call the race a tossup, with the average margin running well inside the high-quality polls’ margin of error.

Pappas leads Brown by a more pronounced margin in available cross-polling, in the range of 48 to 39. That gap reflects Brown’s higher disapproval numbers among independents, who continue to be the largest share of the New Hampshire electorate.

What the Pappas Surge Suggests

For Democrats, the Pappas number in the primary is the most stable they have measured all cycle. After spending much of 2025 absorbing a sustained effort by Manzur and a smaller but determined Sullivan campaign to push the party left, Pappas now has a primary lead that is twice the size of his nearest competitor and is buoyed by sustained television and direct-mail investment in the Manchester and Seacoast media markets.

The Pappas operation has also been working aggressively to lock in endorsements from organized labor, including from skilled-trades unions that have not always defaulted to the Democratic nominee, and from a slate of municipal officials who provide the local validators that pollsters say move late-deciding voters. The 18 percent undecided in this snapshot is unlikely to break uniformly toward Pappas, but the math is reassuring for his team.

The Manzur campaign, asked about the poll, has not conceded any ground. Her organization argues that primary turnout will be driven by lower-frequency voters and that her support is concentrated among younger Granite Staters who are not always represented in landline-weighted samples. That is not a new argument from a primary challenger to a well-funded congressman, but it is one the UNH methodology takes seriously and adjusts for.

What the Sununu Number Means for the GOP

For Republicans, the Sununu number is both a relief and a warning. The relief is that he has not only survived the early-state Brown comeback narrative, he has widened his lead. A 37-point lead on a former senator is the kind of figure that quiets nervous donors and pulls in late-deciding county-committee endorsements.

The warning is that Sununu, who left the governor’s office to mixed reviews in some corners of his own party, is not yet hitting numbers that signal a clear general-election lift. His name recognition among general election voters remains high but polarized, and his favorables among independents are running below where similar GOP candidates would normally want to be at this point.

His campaign team has tried to address that with a deliberately moderate posture on the federal regulatory questions that consume the most space in Washington, particularly on energy policy and the federal land-management decisions that touch New Hampshire’s North Country. Whether that posture can hold through a general election against a Democratic nominee who has spent six years in Congress framing himself as a centrist remains the open question.

Brown has been running a more confrontational, populist campaign that leans into national fights around immigration, federal spending and DOGE-style government reorganization. Brown’s argument to GOP primary voters has been that the moderate path leads back to a Sununu loss, much as it has in past Senate cycles. The 19 percent number suggests he still has room to grow if a Sununu misstep opens a window, but it also confirms that the primary trend line is moving against him.

Why the Race Stays a Tossup

Despite Pappas’s edge in head-to-head matchups, every credible analyst rates the seat as competitive. The presidential off-year cycle, the unusually large undecided pool of New Hampshire independents and the national environment around the Trump administration’s second-term agenda all add volatility that polling at this stage cannot fully capture.

New Hampshire has voted for Democratic senators in three of the last four open Senate cycles, but the margins have varied widely. In 2014, Brown himself fell to Shaheen by just over three points. In 2016, then-Gov. Maggie Hassan defeated then-incumbent Sen. Kelly Ayotte by approximately 1,000 votes statewide. The pattern of close finishes has held even when one party was nominally favored, and there is no reason to expect the 2026 race to break that pattern.

The campaign infrastructure on both sides reflects that reality. National Democratic super PACs have reserved fall airtime in the Boston and Manchester media markets, and the National Republican Senatorial Committee has been building its New Hampshire field operation since last summer. Outside-group spending on the race is expected to reach record levels for a Granite State Senate contest.

For coverage of how the state-level fight has been shaping the political environment Pappas and Sununu will inherit, see our reporting on Gov. Ayotte’s public pressure campaign over the SB 498 children’s mental health initiative. For more on the legislative session that is wrapping up around the race, see our analysis of the NH House decisively setting aside the data center zoning bill. And for the long-running fight over rural Granite State infrastructure that may matter for both nominees’ North Country positioning, see our piece on the five-state advocates’ lawsuit against the Eversource X-178 transmission project.

The Calendar From Here

New Hampshire’s primary elections are scheduled for September 8, 2026, with the general election on November 3. That gives both nominees roughly four months of full general-election campaigning between the primary and Election Day, a window that has historically produced significant late movement in Granite State Senate races.

Pappas will be expected to hold his lead through the summer, with the test coming after Labor Day when paid media saturates the Boston and Manchester markets. Sununu, if he wins the Republican primary as polling suggests he will, will need to find a path to the moderate independents who have powered close Granite State outcomes in past cycles. The Brown lane in the primary tells him that the GOP base wants confrontation. The general electorate may want something different.

There will be more UNH Survey Center data later this summer, and Emerson, Suffolk and St. Anselm’s polling shops are expected to be in the field through the heart of the campaign. RealClearPolling will continue averaging the results, and the aggregate is unlikely to settle into a one-party advantage. For New Hampshire voters, the race remains live, expensive and consequential.

Who is leading the New Hampshire Senate primary in each party?

According to the April 23, 2026 UNH Survey Center poll, Chris Pappas leads the Democratic primary with 61 percent. John Sununu leads the Republican primary with 56 percent. Karishma Manzur is second among Democrats at 18 percent, and Scott Brown is second among Republicans at 19 percent.

What does the general election polling show?

The same UNH poll showed Pappas at 49 percent and Sununu at 42 percent in a head-to-head general election test, with 4 percent backing another candidate and 6 percent undecided. Pappas leads Brown by a wider margin, in the range of 48 to 39 percent, in available cross-polling.

Why is the Senate seat open?

Longtime Democratic Sen. Jeanne Shaheen announced she would not seek a fourth term, opening the seat. The open status of the seat is one of the factors that has made the race a national tossup and attracted significant outside group spending from both parties.

When are the primary and general elections?

The New Hampshire primary elections are scheduled for September 8, 2026, with the general election on November 3. Both major-party nominees will then have roughly two months of full general-election campaigning before Election Day.

How reliable is the UNH Survey Center polling?

The UNH Survey Center is widely cited by national outlets, including FiveThirtyEight, RealClearPolling and the major networks. Its methodology is publicly documented, and its New Hampshire polling has a long track record of being close to final results, although margins of error and undecided voter splits always introduce uncertainty late in a race.

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