Pennsylvania, Georgia, North Carolina, Michigan, Arizona, Wisconsin and Nevada hold the keys to the White House. How have they voted previously – and were they always swing states?
Vice President Kamala Harris and former US President Donald Trump are neck and neck in polls as millions of US citizens head to voting stations on Tuesday.
Both campaigns have been laser-focused on seven key swing states that are likely to decide the eventual winner: Arizona, Georgia, Michigan, North Carolina, Nevada, Pennsylvania and Wisconsin.
Most US states lean heavily, or at least very clearly, towards either Republicans or Democrats. Swing states – also known as battleground states – are the outliers, where support for both parties and their candidates is almost the same.
But the states that meet the bar to be categorised swing states were not always theatres that witnessed close contests.