New Hampshire voters chose electors to represent them in the Electoral College via a popular vote, pitting the Republican Party's nominee, businessman Donald Trump, and his running mate Indiana Governor Mike Pence, against the Democratic Party's nominee, former U.S. Secretary of State Hillary Clinton, and her running mate Virginia Senator Tim Kaine.

As a result, candidates for nomination usually spend a long period campaigning in New Hampshire.

Up until late October 2016, Democrat Hillary Clinton won almost every pre-election poll.

On November 1, just one week before the election, Republican Donald Trump won a poll for the first time, 44% to 42%.

[21] Hillary Clinton's margin of victory was the smallest for a Democrat in the state since Woodrow Wilson narrowly won it in 1916.

Despite Trump's narrow loss, this would be the first and only presidential election since 2000 where New Hampshire would vote more Republican than the national average, when the Republican candidate won more of the state's counties, along with the first time since 1976 when the winner of Coos County did not also carry the state as well.

On September 7, 2017, state House speaker Shawn Jasper announced that data showed that 6,540 people voted using out-of-state licenses.

In February 2017, President Trump had told a gathering of senators at the White House that fraudulent out-of-state voting had cost him and Ayotte the election in New Hampshire.