Van Ostern finished first in the Democratic gubernatorial primary with 53 percent of the vote as of 10 p.m., with former Portsmouth Mayor Steve Marchand second with 25 percent and former Deputy Secretary of State Mark Connolly of New Castle third with 19 percent.
Van Ostern addressed supporters as the Democratic nominee for governor for the first time in the same city where he launched his campaign last October during a roundtable discussion with business and education leaders at Manchester-based SilverTech.
"Together, we will take this next step forward for New Hampshire by bringing and keeping more young people, young families, new businesses and start-ups in our state," Van Ostern said in prepared remarks. "We'll build an economy that works for everyone."