Democrat Mikie Sherrill, a New Jersey lawmaker serving in the US House of Representatives, has won the governor's race in the Garden State.

In one of several races that are seen as an indication of the public mood on the Trump administration's policies, Sherill will succeed Democrat Governor Phil Murphy.

The US Naval Academy graduate, helicopter pilot and ex-federal prosecutor first entered politics in 2018 as anti-Trump sentiment washed over the US during his first term.

Her victory comes after fellow liberal Abigail Spanberger won the Virginia governor's race and New York City elected Democrat Zohran Mamdani as mayor.

With almost all the votes counted, the congresswoman has defeated Republican Jack Ciattarelli, a former state legislator.

At a victory rally, Sherrill said her election win would bring a "new day" for the state.

"I know these are tough times. I know not everyone voted for me - but I'm working for everyone," she said.

She told supporters she would follow the country's founding principles and noted this election sent a message to US President Donald Trump.

"We're going to follow Lady Liberty's beacon. We're not going to give in to our darker impulses," she said. "Here in New Jersey, we know that this nation has not ever been, nor will it ever be ruled by kings. We take oaths to a Constitution, not a king."

The race to lead the state was neck and neck between Ciattarelli, who was endorsed by Trump, and Sherill in the weeks leading up to the 4 November general election in a reliably blue state.

Both focused on cost of living, with Ciattarelli, a businessman and former Republican state representative, proposing lowering personal and corporate tax rates and using a new school funding formula to lower taxes across the state.

Sherrill campaigned on proposed tax incentives for new housing developments and a freeze on utility rate hikes.

State governors are key figures in the US with enormous power that control many aspects of American life, including things ranging from education to abortion rights. Governors have a say on issues decided at the state level.

In New Jersey, governors are limited to two consecutive terms. But they are not limited in non-consecutive terms. The third US state, and one of the original 13 US colonies, New Jersey last had a Republican governor in 2018.

As polling stations opened on Tuesday, the BBC's US partner CBS reported that some polling locations received bomb threats that caused temporary closures and a police response.

Sherrill called the threats "a clear attempt to undermine our democratic system and intimidate New Jerseyans from going to the polls to exercise their right to vote".

Her opponent Ciattarelli told CBS that "there's no place in politics for nonsense like this".