Stefany Shaheen holds a commanding lead in the September 8, 2026, Democratic primary for New Hampshire’s open 1st Congressional District seat, driven by high name recognition as the daughter of longtime U.S. Senator Jeanne Shaheen, early endorsements from multiple mayors and the Teamsters, and a platform centered on healthcare access and opposition to federal cuts. Maura Sullivan, a Marine veteran and former Obama administration official who previously ran for the seat, trails due to weaker organizational support despite stronger fundraising totals. Lesser-known candidates Carleigh Beriont and Heath Howard remain on the margins. Recent candidate forums in May and final filings in mid-June have not shifted the race dynamics, with polling averages from late 2025 and early 2026 showing Shaheen ahead amid high undecided shares. Trader consensus reflects these structural advantages in a district where family political networks and local backing often shape nominations.