Preliminary results from exit polls in 28 key states will give us a glimpse of who's voting and what's motivating their choices.
Bookmark this page now and check back throughout the evening for insights on all the battleground states, from Florida to Ohio, from ABC News' Analysis Desk.
Note: These are preliminary exit poll results; they can change, possibly materially, as the evening progresses. (Read about national exit poll results here.)
Hillary Clinton had a major advantage in get-out-the-vote efforts in this state — 18 percent of voters said they were contacted by the Clinton campaign alone, versus just 5 percent who were contacted by Donald Trump's campaign alone. (Fourteen percent were contacted by both campaigns.)
Party: Thirty-seven percent of voters in Nevada identified as Democrats, versus 27 percent of Republicans in preliminary exit poll results. That's similar to 2012, when Democratic voters outnumbered Republican voters by 10 points on the way to an 8 point Obama victory in the state. That said, among independent voters, Trump beat Clinton by 11 points, 47 to 36 percent.
Religion: Though they voted heavily for Trump, just 14 percent of voters in Nevada were white evangelical Christians — one of the lowest percentages in states where the question was asked. They were outnumbered by nonreligious voters, 27 percent of the electorate, who went for Clinton over Trump by 56 to 30 percent.
Race: As in Arizona, Hispanics were one key to Clinton's fortunes in Nevada. Early exit poll results indicate they accounted for 18 percent of voters in the state, out of 38 percent of nonwhites. Clinton's margins among Hispanics and nonwhites overall fell short of her performance in most other states.
In 2012 non-college whites equaled turnout among nonwhites in Nevada. Tonight they appeared to be slightly behind, accounting for 34 percent of voters in preliminary results, and they broke for Trump by only 19 points, less than elsewhere.
Third party: Independent candidate Evan McMullin brought some excitement to the normally reliably Republican Utah, winning nearly half of Utah voters who have unfavorable opinions of both major-party candidates (38 percent of all voters). McMullin's share was also relatively high among typically Republican groups, including 29 percent of Mormons, 26 percent of Republicans and 21 percent of independents.
Even with those levels of defection, Trump benefited from significant advantages, including a 15 point edge in party identification (narrower than in past years but still large) and winning two-thirds of conservatives, who made up 43 percent of the electorate.
Education: As in other states, Trump won big among whites without a college degree, with 56 percent, versus 22 percent for Clinton and 17 percent for McMullin. Whites with a degree split more evenly, giving McMullin 26 percent of their votes.
Gender: Men broadly supported Trump in Iowa, 56 to 35 percent. That 21 point margin is more than double their 9 point margin for Mitt Romney in 2012 and the largest in exit poll data since 1984.
Education: White women without college degrees, just over a quarter of voters, went from a 17 point margin for Barack Obama in 2012 to even between Clinton and Trump today, 48-48. With a majority of white men backing Trump (as they did Romney), that leaves white college-educated women as the sole group of whites supporting Clinton.
Straying from the party: Partisans strayed from their party's candidates to a greater extent than in the previous few elections. Eighty-nine percent of Democrats supported Clinton, down from 95 percent in 2012; 87 percent of Republicans for Trump, also down, from 93 percent.
Similarly, while the percentage identifying as liberal ticked up slightly from 2012 (24 versus 21 percent), fewer liberals backed the Democratic candidate, 83 versus 89 percent. The share identifying as moderates declined from 42 in 2012 to 38 percent now, as did their margin in favor of the Democrat, from 28 points to 15 points.
Obama: Preliminary exit poll results from Wisconsin suggest Clinton benefited from riding Obama's coattails. Among the 56 percent of the electorate who approve of his job performance, she won 84 to 10 percent, and she won by 95 to 3 percent among voters who want the next president to continue his policies.
Trade: Trump, however, benefited from anti-trade sentiment in the state. Nearly half of Wisconsin voters (49 percent) feel that trade with other countries takes U.S. jobs, and they backed Trump nearly 2 to 1, 61 to 32 percent.
Immigration: At the same time, 57 percent of Wisconsin voters said immigrants do more to help the country than harm it. They supported Clinton by 63 to 28 percent.
Gender: As in many other states, Clinton beat Trump among women (54 to 40 percent) and voters with a college degree (57 to 35 percent), while Trump pushed back with a wide 71 to 24 percent win among white evangelicals, by 66 to 27 percent among non-college white men and by 82 to 12 percent among voters focused on a candidate who can bring needed change to Washington.
Third parties: A greater than average share of Colorado voters opted for third-party candidates this year, capitalizing on the 20 percent of voters in the state with an unfavorable opinion of both major-party candidates. In this group, 28 percent voted for Libertarian Gary Johnson, and 8 percent voted for Jill Stein of the Green Party. Those candidates also did comparatively well with voters ages 18 to 29 (16 percent and 4 percent, respectively) and independent men (14 and 6 percent, respectively).
Race: Whites and Hispanics turned out at rates similar to 2012: 77 and 13 percent, respectively.
Issues: There was not much appetite in Colorado for Trump's hard-line immigration proposals. Only 16 percent supported deporting undocumented immigrants, 37 supported building a wall along the U.S.-Mexico border, and 24 percent said immigrants mainly hurt the country.
That said, there was widespread dissatisfaction and even anger about how the federal government is working. Thirty-one percent were angry and 39 percent dissatisfied, with the former going for Trump by 67 to 18 percent.
Age: Voters 18 to 29 made up a large 26 percent of voters in Arizona in 2012 — generally much higher than in other states. In preliminary results they turned out in fewer numbers this year (just 15 percent, according preliminary results). They voted for Clinton over Trump by 16 points, less than her national margin, with Johnson taking 12 percent, his best group.
Race: Clinton was banking on increased turnout from Hispanics in Arizona to make it close. They accounted for 16 percent of voters in preliminary exit poll results, versus 18 percent in 2012; she won them by 60 to 30 percent in preliminary results, somewhat less of a margin than elsewhere in the country. Nonwhites accounted for 25 percent of voters, compared with 24 percent in 2012, and Clinton won them by just 28 points over Trump, much lower than her margin in this group nationally.
Immigration: Arizona is ground zero for the immigration debate. On one of Trump's signature issues, building a wall along the U.S.-Mexico border, 53 percent of voters there opposed the idea, and 43 percent supported it. They divided by a lopsided 77 to 18 on giving undocumented immigrants a path to citizenship or deporting them. Both results aided Clinton. But 85 percent of voters who support building a wall and 82 percent who want to deport undocumented immigrants voted for Trump.
Independent voters: Independents predominated in early results in Arizona, 40 percent of voters, which could be a high in exit polls since 1992. They divided closely, 45 percent Trump to 42 Clinton.
Race, education: White college-educated women, accounting for about 2 in 10 voters, favored Clinton by 10 points this year, 52 to 42. Last election, they were the only group of whites not to support Romney by a double-digit margin, instead splitting evenly between him and Obama.
White women without college degrees and all white male cohorts supported Trump, topping out at 63 to 26 among white men without degrees.
Blacks accounted for 14 percent of the vote, just below their high in exit polls in 2012, 16 percent. They favored Clinton by an 89 point margin — smaller than the margins among them for Obama in 2008 or 2012 but larger than in any other year.
Unions: Voters from union households supported Clinton over Trump by a 16 point margin, 53 to 37 percent. That's a decline from previous elections, when margins in favor of Democrats were routinely 20 points or more.
Trade: A majority of Michigan voters said that trade generally takes jobs rather than creates them. Despite Trump's strong anti-trade rhetoric, only 53 percent of these anti-trade voters chose him, with 40 percent instead picking Clinton.
Education: Clinton won college graduates by a 22 point margin in preliminary exit poll results in New Hampshire, double the margin for Obama in 2012. And they make up 55 percent of voters, up from 51 percent last election, to a new high for the state. Among whites, she won 63 percent of college-educated women and half of college-educated men. By contrast, in 2012, just over half of the latter group chose Romney.
Hoping for change: Forty-two percent of New Hampshire voters say change is the quality they're looking for most in a presidential candidate. The next closest quality, experience, was picked by just 27 percent, with good judgment and empathy bringing up the rear with 17 and 10 percent. Change voters overwhelmingly picked Trump, while Clinton was favored to varying degrees by those who chose other qualities.
Age: Turnout among seniors (22 percent) was nearly double its average in exit polls through 1984. Seniors have favored Democratic candidates in four of the last six elections and continued to do so this time, albeit by a smaller margin than in 2012 or 2008.
Obama approval: More than half of New Hampshire voters (56 percent) approve of Obama's job performance, and they supported Clinton 86 to 9 percent. New Hampshire went to Obama in 2008 and 2012, by 12 and 6 points, respectively.
The difference in turnout among partisans is razor thin in preliminary exit poll results: 33 percent Democratic, 32 percent Republican and 35 percent independent, making it an archetypal battleground state.
Minorities: Nonwhites accounted for a record 33 percent of voters in Florida in 2012, including 17 percent Hispanics, helping Obama to a close victory there. In preliminary exit poll results, nonwhites make up a remarkable 40 percent of voters, with Hispanics at 18 percent. Non-Cuban Hispanics outnumber Cuban-Americans, 10 percent versus 6 percent. Clinton did very well among nonwhites; Trump came back with nearly 2 to 1 support among whites.
Religion: White evangelical Christians accounted for 24 percent of Florida voters in 2012 and 2008 alike, supporting the Republican candidates by 79 to 21 and 77 to 21 percent, respectively — the single strongest demographic group for the GOP. In preliminary results tonight they accounted for only 20 percent of Florida voters, lower than in previous years, but they voted for Trump 85 to 13 percent, one of the most lopsided results among groups.
Gender: As in North Carolina, women accounted for 54 percent of voters in early exit poll results in Florida, but they favored Clinton over Trump by a narrower margin, 7 points, 51 to 44 percent.
Geography: The largest chunk of voters come from the Miami/Gold Coast area, 28 percent, a very important slice of the Florida electorate for Clinton; they voted for her 2 to 1. Trump did well in the Gulf Coast/mid-Florida region, topping Clinton 2 to 1, and the northern Florida/Panhandle region, winning by 18 points.
Both candidates spent their last night campaigning in Pennsylvania, an important state for each's route to the presidency. Yet 77 percent of voters in preliminary exit poll results say they made up their minds in September or earlier.
Geography: It's a tale of two states in Pennsylvania, with Clinton racking up record margins in Philadelphia and its suburbs and Trump doing the same in the more rural central and northeastern regions of the state, with the two essentially even in the western region around Pittsburgh. In 2012 the Philly suburbs went for Obama by 7 points. This year Clinton won them by 27 points in preliminary exit poll results. Trump expanded his margins elsewhere.
Gender: Views of Trump's treatment of women are sharply negative among female voters — 60 percent in Pennsylvania say it bothered them a lot; far fewer men, 46 percent, said the same.
Race: Race played a part the tight contest in Pennsylvania. Whites made up 8 in 10 voters, similar to 2012, and they went for Trump by a similar margin as for Romney in 2012. But there's movement by education among whites. Whites with and without a college degree picked the GOP ticket in 2012 by similar margins. Tonight, by contrast, Clinton narrowly edged out Trump among white college grads, 50 to 46 in preliminary results, while Trump romped with whites without a degree, 61 to 38 percent.
Views about preferences for whites versus minorities in society divided Pennsylvanian voters nearly in thirds. Thirty-six percent said think whites are favored over minorities, a big group for Clinton; 31 percent said minorities are favored over whites, an equally big group for Trump; and it was tighter among those who saw neither as being more favored.
Religion: Trump was boosted by the large number of white evangelicals in Georgia; they made up 34 percent of voters in preliminary exit poll results and backed him by a vast 88 to 6 percent.
Minorities: Clinton pushed back among the nearly 4 in 10 nonwhite voters (a record if it holds); they backed Clinton by 84 to 12 percent. Blacks made up 29 percent of the electorate, and 90 percent of them voted for Clinton.
Education: Clinton also was boosted by the fact that half the voters in Georgia have a college education (again, a high if it holds); they backed Clinton by 50 to 45 percent.
Geography: There were vast regional divides in vote preference. Voters in the south of the state backed Trump by 66 to 30 percent (a flip from 2008, when they favored Obama by 54 to 46 percent) as did voters in northern Georgia, 67 to 26 percent. In the Atlanta metro area, however, Clinton had even stronger support, 76 to 20 percent. Trump had a wide 37 point advantage over Clinton in rural areas of the state (65 to 28), more than double John McCain's margin there in 2008. But preliminary data indicated that fewer rural residents turned out to vote this time.
Gender gap: Sharply negative reactions to Trump's treatment of women may lead to a record gender gap among Virginia voters. Preliminary exit poll results give Clinton a 19 point advantage among women, 57 to 38 percent.
Further, 55 percent of voters said they were bothered a lot by Trump's treatment of women — rising to 62 percent of women in the state.
Geography: While turnout patterns by region are similar to 2012's, Clinton was powered by big margins in the D.C. suburbs and particularly in the Northern Virginia exurbs. The latter split evenly between Obama and Romney in 2012 but went for Clinton 51 to 43 percent in preliminary exit poll results. She won those who were not born in the Commonwealth nearly 3 to 1, 70 to 26.
That said, Trump's margin in the central and western regions of the state kept him in the game; he won this rural region by 29 points in preliminary results, versus 23 points for Romney in 2012. Turnout among evangelical white Protestants increased slightly from 2012, and similar to 2012 for Romney, it's one of Trump's best groups, 75 to 15 percent in preliminary exit poll results. Trump also won among voters in gun-owning households, by a 17 point margin.
Gender gap: Fifty-four percent of voters in North Carolina preliminary results are women, and they voted for Clinton over Trump by 13 points. Trump, however, came back with a strong showing among men. The gender gap could be a record.
Race: Thirty percent of voters were nonwhite, with 21 percent black — both close to their levels in 2012, 30 and 23 percent, respectively. Nonwhites went for Clinton 80 to 15, slightly off Obama's 88 to 12 percent in this group 2012. Again, Trump pushed back with a big advantage among white voters.
Education: One of Trump's strongest groups, non-college whites, accounted for 37 percent of voters in 2012, more than the share of minorities. Tonight in North Carolina, early results suggest they may fall short of their 2012 numbers; the current estimate is 32 percent, versus 38 percent college-educated whites. In 2012 and 2008, non-college whites outnumbered college-educated whites; that may flip this time. That said, Trump beat Clinton among non-college whites more than 2 to 1, 67 to 27 percent.
HB2: Sixty-six percent of North Carolina voters say they oppose the so-called bathroom law, and they favored Clinton over Trump by about 2 to 1. Those who support the law were a strong Trump group.
Nearly half of voters, 49 percent, were not born in North Carolina, a very high proportion of the vote. Fifty-one percent were native North Carolinians. The former broke for Clinton, the latter for Trump.
Time for change: A plurality of Ohio voters, 42 percent, said that having a candidate who could bring needed change was the most important candidate attribute, a huge group for Trump. Voters split on which of the other attributes (empathy, experience and judgment) were most important — all better groups for Clinton, albeit by less of a margin in each case.
Economy: The economy loomed large in the minds of Ohio voters; 54 percent identified it as the most important problem. Sixty-one percent said that the economy is in not so good or poor shape, and Trump led in this group by 69 to 26 percent. But among more optimistic voters, Clinton led by even more. And it was a close 50 percent Trump to 46 Clinton on who would better handle the economy.
The Kasich effect: While 53 percent of voters had a favorable opinion of Ohio Gov. John Kasich, his popularity is not helping Trump. Kasich did not endorse Trump, and only 39 percent of those who had a favorable opinion of Kasich voted for Trump.
Unions: Clinton's struggled with union households, normally a pillar of the Democratic coalition. There was no difference in votes between union and nonunion households today; in 2012, Obama won union households by 23 points.
Exit polls, the surveys conducted as voters leave their polling place, rely on random sampling of voters. Because so many people vote early or by mail, this year's exit polling included telephone polls conducted in states with a high percentage of early or absentee voters. Learn more about the process here.
ABC News' Suzanne Dacunto, Donald Pearsall and Linda Fisher contributed graphics to this report.