Manchester, New Hampshire: Senator Bernie Sanders and Republican Donald Trump have won emphatic victories in the New Hampshire primary, with voters turning savagely on insider political figures in both parties.
Clinton: 'I still love New Hampshire'
RAW VIDEO: Hillary Clinton congratulates rival Bernie Sanders, telling supporters: "It is not whether you get knocked down that matters, it's whether you get back up."
Such was the size of their respective victories that US media outlets were able to confidently project their victories once the second polls closed at 8pm.
Sanders supporters at a campaign watch party in New Hampshire exploded with joy at the news, and cheered again minutes later when it was reported that Hillary Clinton, the Democratic front runner, was soon expected to call the democratic socialist senator from Vermont to concede to him.
The New Hampshire primary, held shortly after the Iowa caucuses, are the first primary election in the nation and considered a crucial test of the viability of the candidates.
With 12 per cent of the vote counted shortly before 9pm Mr Trump led the Republican race with 34 per cent of the vote.
His nearest rival was the Ohio governor, John Kasich, who had secured 16 per cent. Mr Kasich is seen as a moderate in the Republican race, having embraced President Barack Obama's healthcare law and declined to engage in the fierce anti-immigration rhetoric that has become party orthodoxy since Mr Trump took the lead.
But Mr Kasich remains a tough anti-union activist and as governor has worked hard to restrict access to abortion in his state.
Should he maintain his lead for second place his campaign will be reinvigorated as he makes the case to party elders that he is a legitimate alternative to Mr Trump, who the party establishment does not believe can win a presidential election against Mrs Clinton.
In turn this will increase the flow of donations to his war chest.
The Kasich campaign has already dispatched funding, volunteers and staff to South Carolina and Nevada, CNN reported.
Normally the New Hampshire primary thins the field, but as counting continued Jeb Bush, the former Florida governor, remained in striking distance of Mr Kasich, as did the freshmen senators Marco Rubio and Ted Cruz.
None of them have so far been dealt a knockout blow. This tight race benefits Mr Trump, as the party has yet to find an alternative to him that it can coalesce around.
On the Democratic side, Mrs Clinton's campaign wasted no time in conceding a contest they had not hoped to win for weeks. The goal for Clinton has been to limit the size of Sanders' victory in New Hampshire, which is a neighbouring New England state to his own Vermont. However, early returns show Sanders beating the former secretary of state by a double-digit margin, 58 percent to 42 percent.
Her campaign will now focus on South Carolina, where she is expected to win, partly due to the support she enjoys among African Americans and Hispanics.