Donald Trump will be the 45^th President of the United States with American voters handing him a stunning mandate to govern the world’s most powerful nation.

Despite trailing in most opinion polls in the last month, the 70-year-old New York property developer will take control of the White House next January after a bitterly-fought presidential race against Hillary Clinton.

The controversial candidate has claimed at least 276 delegates to 218 for Ms Clinton.

The prospect of a Trump victory soared late on Wednesday morning (AEDT) as the results of early counting in key swing states such as Florida and North Carolina sparked big falls on Asian stock markets.

Mr Trump’s presidency is expected to transform America’s strategic role in world affairs because of his promises to tear up free trade agreements, reinstitute tariff protection and wind down US intervention in foreign conflicts.

These policies are likely to have swayed thousands of blue-collar voters in traditional Democratic-voting states in America’s Midwest.

Mr Trump has won or is looking good to win several so-called rustbelt states – including Michigan and Wisconsin – that have been locked up by Democratic nominees for almost thirty years.

Not since George H. Bush’s big victory in 1988 has a Republican presidential candidate won Michigan, and the neighbouring state of Wisconsin last voted Republican in Ronald Reagan’s 1984 landslide.

Mr Trump has also taken delegate-rich Pennsylvania, which has seen its steel-making industry cave in to competition from cheap Chinese imports.

A measure of Mr Trump’s presidency will be his ability to deliver the protectionist trade policies he promised throughout the campaign and also to demonstrate their benefits to working-class families in towns and cities throughout Ohio, Michigan and Wisconsin.

Late swing seals Trump’s victory

Only one national poll predicted a Trump victory. Photo: Getty

While most of the opinion polls accurately forecast Ms Clinton’s popular vote at around 47 per cent, most underestimated Mr Trump’s national support, which has come in at around 48 per cent.

A third party candidate, Gary Johnson, appears to be the main reason the opinion polls got the national result very wrong.

The final opinion polls published by media companies on Monday showed Mr Johnson sitting on about 5 per cent of the national vote.

He ran as the Libertarian Party’s nominee and was attracting support from traditional Republican voters who appeared to be disaffected with Mr Trump.

However, the election count shows that Mr Johnson’s vote collapsed on election day with most flocking to Mr Trump, particularly in Florida and Ohio.

Only one national poll predicted a Trump victory – the IBD/TIPP survey – which forecast a two percentage point margin for the Republican nominee.

The IBD/TIPP poll has outperformed most other pollsters at the last four presidential elections, including near-perfect forecasts in 2004 and 2008.

Florida does it again

Florida’s status as a kingmaker in US presidential elections was also underlined, with Mr Trump claiming the state’s 29 electoral delegates in a stunning upset.

While a late poll published on Monday tipped that Mr Trump would take the state by a small margin, some polls had Ms Clinton winning by as much as 2 percentage points.

While exit surveys showed that a majority of Hispanic voters backed Ms Clinton, her support from ethnic minorities was lower than that enjoyed by Barack Obama in 2012.