The two candidates are neck and neck in the polls after a dramatic campaign that has seen two assassination attempts against Donald Trump and the shock withdrawal of President Joe Biden from the race.
Millions of Americans are voting in an historic election that could put Donald Trump back into the White House or make Kamala Harris the first woman to become US president.
The two candidates are neck and neck in the opinion polls after a bitter campaign that saw two assassination attempts against Republican Mr Trump as well as the shock withdrawal of President Joe Biden.
In around 100 days since replacing Mr Biden, Ms Harris has found her feet and mounted a fierce challenge to her opponent.
The final hours of voting are under way and polls have already closed in six states, including Georgia - one of a handful of battleground states that could decide the election.
Early projections from NBC News show Ms Harris winning Vermont, Massachusetts and Maryland and Mr Trump taking Florida, South Carolina, Kentucky, Indiana, Missouri, Oklahoma, Tennessee, Alabama and West Virginia, in the first results of the night.
| State | Electoral votes | Votes left | Margin | Currently leading |
|---|---|---|---|---|
| GA | 16 | 47% | 11.4% | Trump |
| Del | 3 | 52% | 14.7% | Harris |
| Rd Isl | 4 | 57% | 4.8% | Harris |
| Texas | 40 | 58% | 5.4% | Trump |
| Ohio | 17 | 59% | 1.4% | Trump |
| VA | 13 | 61% | 1.4% | Harris |
| N Jer | 14 | 78% | 10.9% | Harris |
| N Ham | 4 | 81% | 9.1% | Harris |
| N Car | 16 | 86% | 0.5% | Harris |
| Kansas | 6 | 92% | <0.1% | Harris |
| Penn | 19 | 92% | 43.5% | Harris |
| Mich | 15 | 94% | 17.7% | Harris |
| Missi | 6 | 96% | 13.7% | Trump |
| Ill | 19 | 98% | 33.8% | Harris |
| Maine | 4 | 99% | - | Trump |
| Con | 7 | 99% | 12.7% | Harris |
| S Dak | 3 | 100% | - | |
| N Mex | 5 | 100% | - | |
| Iowa | 6 | 100% | - | |
| Ariz | 11 | 100% | - | |
| Nev | 6 | 100% | - | |
| Alaska | 3 | 100% | - | |
| Oregon | 8 | 100% | - | |
| Nebr | 5 | 100% | - | |
| Wash | 12 | 100% | - | |
| Minn | 10 | 100% | - | |
| NY | 28 | 100% | - | |
| N Dak | 3 | 100% | - | |
| Col | 10 | 100% | - | |
| Idaho | 4 | 100% | - | |
| LA | 8 | 100% | - | |
| Wis | 10 | 100% | - | |
| Wyo | 3 | 100% | - | |
| Utah | 6 | 100% | - | |
| Hawaii | 4 | 100% | - | |
| Mont | 4 | 100% | - | |
| Cali | 54 | 100% | - |
Voting on Tuesday appears to be smooth, with only scattered reports of delays from extreme weather, long lines or technical problems.
The FBI reported that there had been "non-credible" bomb threats to several states, some of which it said came from Russian email domains. The Russian embassy said accusations of interference were "malicious slander".
