The polling stations have opened in Connecticut, Indiana, Kentucky, New Hampshire, Maine, New Jersey, New York, and Virginia.
Earlier in the day, Dixville Notch, a tiny township in New Hampshire with the population of less than 10 people, become the first place in the US to report its election results. Kamala Harris and Donald Trump, the presidential candidates, tied in the unincorporated US township as they received three votes each.
Six people voted Dixville Notch just after midnight ET (05:00 am GMT) when the polls opened according to a tradition that dates back to 1960s.
The incumbent vice president, Harris, a Democrat, and former President Trump, a Republican, are competing for the country's top job. The close race is expected to come down to a handful of battleground states - Pennsylvania, North Carolina, Georgia, Michigan, Arizona, Wisconsin, and Nevada.
All 435 seats in the House of Representatives and 34 of the 100 seats in the Senate are also up for election on November 5.