Americans are choosing their next president, in a contest being closely watched around the world.

The race is exceptionally close and either Vice-President Kamala Harris or former president Donald Trump could win.

Voters also selecting members of Congress, politicians who play a key part in passing laws that can have a profound effect on life in the US.

The 2024 election is on Tuesday, 5 November 2024.

Ahead of election day, tens of millions of voters have taken part in early voting events across the US.

The winner will serve a term of four years in the White House, starting in January 2025.

On the world stage, the US leader has considerable freedom to represent the country abroad.

Within the US, the president has the power to pass some laws on their own but he or she must mostly work with Congress to pass legislation.

Former president Donald Trump is representing the Republican Party. He won the party's support with a massive lead over his rivals.

Trump chose Ohio senator JD Vance to be his vice-presidential running mate.

Kamala Harris, the current vice-president, is the candidate for the Democratic Party. She joined the race after President Joe Biden dropped out and no other Democrats stood against her.

Her running mate for vice-president is Minnesota Governor Tim Walz.

There are also some independent candidates running for president. One of the most prominent was Robert F Kennedy Jr, but he suspended his campaign in August and backed Trump.

The Democrats are the liberal political party, known for supporting civil rights, a social safety net and measures to address climate change.

In the 2024 election, issues highlighted by Harris include tackling the cost-of-living crisis and supporting abortion rights.

The Republicans are the conservative political party. They have stood for lower taxes, shrinking the size of the government and gun rights.

Issues Trump has campaigned on include tackling illegal immigration and ending inflation to "make America affordable again".

The winner is not the person who gets the most votes overall.

Instead, both candidates compete to win contests held across the 50 states.

Each state has a certain number of so-called electoral college votes, partly based on population. There are a total of 538 up for grabs and the winner is the candidate that gets 270 or more.

All but two states have a winner-takes-all rule, so whichever candidate has the highest number of votes is awarded all of its electoral college votes.

Most states lean heavily towards one party or the other, so the focus is on about seven states where either of them could win. These are known as the battleground or swing states.

It is possible for a candidate to win the most votes nationally - like Hillary Clinton did in 2016 - but still be defeated.

Most US citizens aged 18 or over are eligible to vote.

Each state has its own voter registration process and deadline.

US citizens who live abroad can register and request an absentee postal ballot.

All of the attention will be on who wins the presidency, but voters will also be choosing new members of Congress - where laws are passed - when they fill in their ballots.

Congress consists of the House of Representatives, where all 435 seats are up for election, and the Senate, where 34 seats are being contested.

Republicans currently control the House, which initiates spending plans. Democrats are in charge of the Senate, which votes on key appointments in government.

These two chambers pass laws and can act as a check on White House plans if the controlling party in either chamber disagrees with the president.

Usually the winner is declared on the night of the election, but in 2020 it took a few days to count all the votes.

The period after the election is known as the transition, if there is a change of president.

This gives the new administration time to appoint cabinet ministers and make plans for the new term.

The president is officially sworn into office in January in a ceremony known as the inauguration, held on the steps of the Capitol building in Washington DC.