Democratic voters in New Hampshire's 1st Congressional District went to the polls in a tightly contested primary to choose a candidate for the seat being vacated by Rep. Chris Pappas, who is running for the US Senate. Early Wednesday morning the race remained too close to call, with Stefany Shaheen, daughter of retiring Senator Jeanne Shaheen, holding a narrow lead over Maura Sullivan, a former Obama administration official, in a contest seen as important to the party's efforts to hold the seat.

Shaheen finished Tuesday night roughly two percentage points ahead of Sullivan, despite being outspent, having raised $2.4 million in campaign contributions compared with Sullivan's $3.6 million; she also had the backing of her mother, who endorsed her last year. State legislator Carleigh Beriont trailed both frontrunners by almost ten points but still secured around 20% of the vote, in a field that included eight other contenders. Shaheen has campaigned on Medicare for All, tax breaks for first-time homebuyers and reforming ICE, while Sullivan, a Marine veteran and former VA official, has focused on tackling price gouging, strengthening veterans' services and opposing Trump-era tariffs. The winner will face the Republican nominee in the general election on 3 November.