US voters head to the polls on Tuesday with US Vice President Kamala Harris and former president Donald Trump in a dead heat. But the future of the US Congress is also up for grabs, with voters choosing all 435 members of the House of Representatives and a third of the seats in the Senate. A spate of referenda are also on the ballot, on everything from abortion to trophy hunting.

Here is a look at who and what is up for a vote beyond the choice between Republican Donald Trump and Democrat Kamala Harris.

Congress

In addition to choosing a president, millions of US voters will decide the fate of Congress: both in the House of Representatives -- where all seats are up for grabs -- and the Senate, where one-third are.

The House of Representatives has 435 members, with each representing a Congressional district and elected for a two-year term. Republicans presently hold the House by a small margin, with the election so tight it is a true toss-up for who will win control.

Thirty-four of the Senate's 100 seats are in play. The Senate consists of two senators from every state, who hold six-year terms. Democrats are in control now, but Republicans may well flip the chamber by a razor-thin margin.

If the same party were to win the presidency and both houses of Congress, it would have the power to push through the president's agenda without support from opposition lawmakers.

Governors

Gubernatorial elections will occur in 11 of the 50 US states, with key races in New Hampshire, North Carolina, Indiana and Washington state.

The governor is the top executive at the state level, where most powers that do not belong to the federal government lie.

Referendums

Since the federal right to an abortion was overturned in 2022 by the Supreme Court, the issue has been omnipresent on the political landscape.

Democrats are trying to use the debate over reproductive rights to dissuade women voters from casting ballots for Republicans.

Abortion rights will be the subject of referendums in some 10 states. Voters in Nebraska will even vote on two competing abortion referendums -- one prohibiting it after 12 weeks and another allowing it until fetal viability.

In dozens of states, voters are being asked to decide on a variety of other issues.

In Colorado, for example, voters will decide whether or not to ban "trophy hunting" of the mountain lion, bobcat and lynx.

And in Maine, voters will decide if they want to change their state flag.

Local elections

Thousands of local offices will also be up for election, including state-level lawmakers, judges, mayors, city council members, county officials, sheriffs and others.