Billionaire and former reality TV host Donald Trump has done the almost unimaginable, rolling into the White House to become the leader of the free world.
"Sorry to keep you waiting... complicated business," Trump told supporters at 2.50am New York Time.
"It is time for us to come together as one united people... it's time. I will be president for all Americans."
He said he had spoken to Hillary Clinton in a phone call, congratulating her on a hard-fought campaign.
It is an astonishing victory for a celebrity businessman and political novice who capitalised on voters' economic anxieties, took advantage of racial tensions and overcame a string of sexual assault allegations on his way to the White House.
Trump's triumph over Hillary Clinton will end eight years of Democratic dominance of the White House and threatens to undo major achievements of President Barack Obama.
Conservative America has sent Trump to Washington on a mission to "make America great again" - but markets have slumped amid the surprise at the appointment of the unlikely President.
Layne Bangerter, director of the Trump for President campaign in Idaho, told the Press Association: "The voice of the people has risen up."
Trump rolled into the White House on the back of victories in crucial swing-states Florida, Ohio, and North Carolina.
EARLIER
Donald Trump is rolling towards the US presidency in one of the tightest races imaginable, sending shockwaves across markets and the world.
The result has left the Democrats devastated, with Hillary Clintonnot appearing at her own campaign HQ party in Manhattan tonight. Campaign chairman John Podesta refused to concede and said votes were still too tight in some states.
Trump has won the swing-states of Florida, North Carolina and Ohio, and with them, likely the ticket to be the 45th president of the United States. He is more than 50,000 ahead in Pennsylvania, a Democrat stronghold, and Michigan; and slightly behind in New Hampshire.
Trump has 264 electoral votes and Clinton has 215 in the crucial race to 270.
Trump has left the war room for the first time tonight, heading to his penthouse in Trump Tower in New York to take "a moment with his wife" Melania, Sky News reports.
The change in the frame of mind from the Clinton supporters on the street in New York could be felt within about half an hour, reports news.com.au's Charlotte Willis.
First they were declaring, "we're not worried" and "it's early days", and now there is just dead silence. Video from within the Clinton campaign shows her entire camp at a standstill.
The New York Times is predicting an 94% likelihood of Trump winning the presidency; statitisican Nate Silver puts it at 77%.
In an indication of the increasing confidence in the Republican nominee's camp, a senior aide at his New York "victory party" said Trump had won the bitterly fought presidential race.
Layne Bangerter, director of the Trump for President campaign in Idaho, told the Press Association: "I'm saying it's over. The voice of the people has risen up."
Trump won Florida after the lead swung between both candidates over the afternoon. Ohio and North Carolina were two other must-win states for him to win the presidency.
Clinton just clung on in Virginia, a state she was expected to win easily. Trump is leading in Michigan and Wisconsin.
Westpac senior markets strategist Imre Speizer said while the markets were expecting a Clinton win early on, this had swung to thinking Trump would win. The NZX is down 3%.
"This team has so much to be proud of. Whatever happens tonight, thank you for everything," Clinton tweeted in the past hour.
Trump has won more than 20 states including Texas and Arkansas and Hillary Clinton has won more than a dozen states including New York, Vermont, Illinois, New Jersey, Massachusetts, Maryland, Delaware, Rhode Island and Washington D.C. None of those states were expected to be competitive.
Earlier in the evening, CNN reported sources as saying Donald Trump's own internal polling was showing a "tough night" ahead, but the mood at his headquarters in Manhattan is now much more buoyant.
Former Republican president George W Bush did not vote for Trump, according to a spokesman.
WATCH LIVE: NZ Herald Focus election special - app and mobile users click here to view the stream.
In California, at least one person was killed and three people injured after a shooting near a voting booth, the Los Angeles Times reported.
The question remains, can Hillary Clinton recover from FBI announcements about her emails and become the first Madam President, or will businessman Donald Trump get to the White House? Enjoy live updates from nzherald.co.nz as results come in.
Both Clinton and Trump delivered their final messages during the final campaign sprint yesterday.
Clinton told a rally: "What will you say when your grandkids ask 'what did you do in 2016'?"
Trump tried to end on a positive note, telling supporters: "I'm asking you to dream big, I will fight for you."
Key states to watch are Florida, North Carolina, Pennsylvania, Ohio and Virginia.
They are among the earliest to finish voting late this morning NZT.
More than 40 million people voted early.
Putin signed a decree that enables nuclear weapon use against non-nuclear states.