The United States is made up of 50 states, but, when it comes to presidential elections, some states matter more than others.
Though "safe states" reliably vote for one party or the other, "swing states" are often a toss-up between the Democratic and Republican candidate and, with 10-19 Electoral College votes per state, they are particularly attractive to campaigns.
As the US president and vice president aren't elected directly by voters through the national popular vote, swing states are put under the polling microscope, host high-profile rallies, receive numerous visits from candidates and are inundated by party ads targeting undecided voters.
This complex and controversial process has recently meant that the winner of the popular vote could fail to win the Electoral College, and thus the presidency. This happened in 2000 when George W. Bush beat Al Gore, and in 2016 when Donald Trump was chosen over Hillary Clinton.
Which states are swing states?
Over the years, the list of swing states has changed because of population growth and shifting demographics. Still, for US voters the economy and inflation are at the top of the list of important issues.
Stances on abortion rights will play an important role in voter turnout across the country. Besides these topics, each swing state has its own set of key issues.
Arizona
Arizona shares a long border with Mexico.
As vice president, Kamala Harris was given the job of reducing the number of people attempting to cross the US's southern border by tackling the "root causes" of emigration from Latin America. Her Republican opponent in the 2024 election campaign, former US President Donald Trump, and his supporters say she failed at this task.
To boost its economy, Arizona is beefing up its manufacturing sector. The CHIPS Act, a law introduced by President Joe Biden, is helping fund billions for computer chip plants, but it will be a while until these new facilities are up and running.
Biden won the state in 2020.
Electoral votes: 11
Georgia
In 2020, Biden became the first Democrat to win Georgia's electoral votes since Bill Clinton in 1992. But with a margin of 0.2 percentage points, it was an incredibly tight race.
About 33% of the state's voters are Black, one of highest proportions in the country — a fact that may come in handy for Harris.
Georgia is also the state where a grand jury indicted Trump and 18 others on charges related to illegally trying to overturn the 2020 presidential election. That case has stalled and won't go to trial before the current election.
Electoral votes: 16
Michigan
It's nearly impossible to think of Michigan without the auto industry. The state is home to Ford, General Motors and Chrysler, now part of Stellantis. These manufacturing jobs are important to the region. An invasion of competitive Chinese electric vehicles was recently stopped in its tracks by massive tariffs introduced by Biden.
The state is also home to Gretchen Whitmer, a popular Democratic governor who has long been a thorn in the side of Republicans.
Yet, in the February presidential primaries more than 101,000 voters chose the "uncommitted" option to show their frustration with Biden during the war in Gaza. Now that he has been replaced, Harris needs to secure their backing.
Harris will also need to win over Michigan's large pool of Arab American voters. Their support of the Democrats has been in jeopardy because of the party's backing of Israel in its war against Hamas in Gaza.
Biden won the state in 2020.
Electoral votes: 15
Nevada
Immigration is a key issue for Nevada, because of its location near the southern border. The population is nearly one-third Hispanic.
Nevada state is heavily dependent on tourism, and its economy has grown more than that of any other swing state since Biden took office. At the same time, it has the highest unemployment rate of any state in the country.
Biden won the state in 2020.
Electoral votes: 6
North Carolina
North Carolina is the latest to join the list of swing states. Before Biden dropped out of the race in July, Trump had a big lead here. Harris has been able to bring that to a near tie. Yet Democratic presidential candidates have only taken the state one time in the past 11 elections.
The state has seen big demographic changes and gone from 75% white in 1990 to about 60% today. Over the last 30 years, the total population has increased significantly. The state has attracted a wide range of people, from military veterans and retirees to young college grads.
Trump won the state in 2020.
Electoral votes: 16
Pennsylvania
Fracking has made Pennsylvania the country's second-biggest natural gas producer, after Texas. Trump has long promoted fracking. Harris previously called for a ban but she is now keeping options open, albeit with stricter regulations.
Pennsylvania also hosted the only debate between Harris and Trump, on September 10.
Biden won the state in 2020.
Electoral votes: 19
Wisconsin
In Wisconsin, white people make up a higher percentage of the electorate than in any other swing state.
In the past two presidential elections, Wisconsin had one of the highest voter turnout rates in the country.Residents were able to pick the winning presidential candidate in both 2016 and 2020 by a margin of fewer than 25,000 votes each time, showing just how important each vote can be in a swing state.