But if you want to get an idea of which way things might be headed, we've identified several races that might give you a sense of the way the political wind is blowing (organized by poll close time):
(We get into greater detail of specific House races to watch here and the Senate here.)
7 p.m. ET: Georgia, Indiana, Kentucky, South Carolina, Vermont, Virginia
Let's get things started! All eyes are on Georgia and Virginia with a House race to watch in Indiana, too.
GA SEN: This race is crucial to Senate control. The race is expected to be exceedingly close, so it almost certainly won't be a poll-close call and may not even be decided for weeks. (NPR doesn't make calls. We rely on The Associated Press.) The number to watch is 50%. A candidate needs to top that mark to avoid a Dec. 6 runoff. There's a libertarian on the ballot who may prove to be a landing place for a lot of protest votes, so we might not know the result of this race – and possibly control of the Senate – for a month.
IN-1: Democratic incumbent Frank Mrvan is facing a tough challenge in a district that after redistricting, President Biden would have won in 2020 by a few percentage points. If Mrvan is struggling, it could be a big night for Republicans.
VA-2, 7, 10: Incumbent Democrats Elaine Luria (VA-2) and Abigail Spanberger (VA-7) are in toss-up races. But also watch Jennifer Wexton's race in the 10th against Republican challenger Hung Cao. This race has seen lots of ad spending, and the Jan. 6 insurrection has been a factor in this race (as well in VA-2 because Luria is on the Jan. 6 committee). Wexton is favored, so if she is down early, it could be a sign of things to come. But remember in Virginia, a lot of rural counties report their vote first and often Democratic margins expand as the night goes on because of more populous areas in north Virginia, especially Fairfax County.
7:30 p.m. ET: North Carolina, Ohio, West Virginia
Ohio and North Carolina have top Senate races and House races to watch:
OH SEN/NC SEN: Democrats had been hopeful of having a shot at picking up these two seats, but have become less so in recent days. The margins will be telling either way. If Democrats keep it within a couple points, control of the Senate will likely take a long time to figure out – probably beyond election night. On the other hand, if these are poll-close calls for Republicans, the GOP could be headed for Senate control.
OH-1: A poll-close call in favor of Republican incumbent Steve Chabot would be a good sign for Republican control of the House. It went 51%-48% for Trump in 2020, so Democrats likely have to be competitive here to have a chance at holding on.
OH-9: Incumbent Marcy Kaptur (D) is facing Air Force veteran J.R. Majewski (R). Majewski is about as MAGA as it gets. Kaptur is favored, but the margin will be telling.
8 p.m.: Alabama, Connecticut, Delaware, District of Columbia, Florida, Illinois, Maine, Maryland, Massachusetts, Mississippi, Missouri, New Hampshire, New Jersey, Oklahoma, Pennsylvania, Rhode Island, Tennessee
Polls would now be closed in half the country, and this hour is a deluge – 16 states, eight governors races, four Senate seats and half a dozen House seats to watch. Expect poll-close calls in governors races in favor of Republicans in Alabama and for Democrats in Connecticut, Illinois and Maryland.
Here are some of the races to keep an eye on:
FL GOV: Gov. Ron DeSantis, R-Fla., is favored and has gotten lots of attention as a potential 2024 GOP candidate and replacement for Trump. In the Senate race, Marco Rubio is favored to win reelection as well, as Florida continues its lurch from swing state to red state.
NH SEN: Democrat Maggie Hassan is favored against Republican challenger retired Army Brig. Gen. Don Bolduc. Bolduc was not Republican leadership's choice. He hasn't raised or spent much money, is farther to the right than the majority of the state ideologically. But if he's close, that could mean a big night for Republicans in the Senate.
PA SEN: This might be the most important race of the night. For Democrats to have a hope of holding the Senate, they probably have to win here. Don't expect a poll-close call. Be very careful in reading early results. There may be a few shifts as the night goes along – initially in favor of Democrat John Fetterman because of early vote results, but then a shift toward Republican Mehmet Oz as in-person votes are tabulated, and then again much later in the evening toward the Democrats again, as early vote results, which take longer to count, and very populous Philadelphia, are finalized. So hold on tight.
There are about half a dozen House races in this hour that could tell us about control of the chamber. Here, we spotlight two:
ME-2: Democratic incumbent Jared Golden is sitting in a district Trump won. If Golden loses, it would likely confirm a GOP takeover and give Republicans their only seat in New England. They are for two other New England seats, including CT-5, which is also up in this hour – and one in Rhode Island, as well. And also keep an eye on some of the New Jersey House races that came on the board in only the last week or so.
IL-17: Both parties are watching this one. If the Democrat here wins, Democrats might be stemming some of the GOP tide. But if not...
8:30 p.m.: Arkansas
Expect a poll-close call in favor of Republican John Boozman to be re-elected to the Senate – and, yes, for Sarah Huckabee Sanders to be governor of Arkansas. Sanders, the former Trump White House press secretary, is set to follow in her father's (Mike Huckabee) footsteps as governor of the state. Sanders underwent surgery last month after a biopsy revealed she had thyroid cancer. She said after her surgery that she was "cancer-free."
9 p.m.: Arizona, Colorado, Iowa, Kansas, Louisiana, Michigan, Minnesota, Nebraska, New Mexico, New York, North Dakota, South Dakota, Texas, Wisconsin, Wyoming
Now, we're in the thick of it – 15 more states, as well as continued results rolling in from the earlier 27. There will likely be poll-close calls for the Senate races in Kansas, Louisiana, New York, and North and South Dakota, as well as in gubernatorial races in Colorado, Nebraska, South Dakota and Wyoming.
But there are ample storylines in this hour:
three top Senate races (Arizona, Colorado and Wisconsin);
whether election denier Kari Lake wins for governor of Arizona and what that means about the state where immigration is such a key issue;
crime as an issue, like in the Wisconsin Senate race, where Ron Johnson is trying to grit out reelection, and in the New York governor's race;
the margin in the Colorado Senate race and whether incumbent Democrat Michael Bennet – who used abortion as a top focus against a moderate Republican who said he would "actively" campaign against a 2024 Trump run – does well;
Beto O'Rourke's challenge of Gov. Greg Abbott in Texas;
how well longtime Sen. Chuck Grassley holds up in his race, which has gotten more competitive;
how well Democratic gubernatorial candidates hold up in the Midwest (Minnesota, Michigan and Kansas). Minnesota and Michigan lean toward Democrats, but will Republican-leaning voters in Kansas again crossover and keep a moderate in the governor's seat?
An abortion rights ballot measure in Michigan.
For the House, watch the races north of New York City and on Long Island. There are seven House races to watch in New York, and for the last 15 years or so, these moderate areas have been some of the strongest bellwethers of which way the wind is blowing for control of the House.
10 p.m.: Montana, Nevada, Utah
All eyes are on Nevada, one of the tightest Senate races in the country, but the Senate race in Utah is an interesting one, as is a new House race in Montana.
NV SEN: Democratic incumbent Catherine Cortez Masto is neck and neck with Republican former state Attorney General Adam Laxalt. Laxalt was one of the leaders of Trump's efforts to overturn 2020 presidential election results in the state. Don't expect a poll-close call, because this one should be very close.
NV GOV: Democratic Gov. Steve Sisolak is also in a close fight for a second term against Republican challenger Joe Lombardo, the sheriff of Clark County. Inflation is top of mind for voters, as rent and gas costs have risen faster in the state than almost anywhere else in the country.
UT SEN: Democrats didn't field a candidate against incumbent Mike Lee (R), clearing the way for Evan McMullin's independent bid. Polls in this race have been all over the place, and both Republican Gov. Spencer Cox and Republican Sen. Mitt Romney have withheld their endorsements.
MT-1: Due to population growth, Montana has a new House seat. Former Trump Interior Secretary Ryan Zinke is in a competitive race against Democrat Monica Tranel.
11 p.m.: California, Idaho, Oregon, Washington
Hello, West Coast! It's like a whole new election night has begun.
Expect poll-close calls in favor of California Sen. Alex Padilla, who would be elected for the first time – he was appointed to replace Kamala Harris in 2021; for Gov. Gavin Newsom, Idaho Sen. Mike Crapo and Oregon Sen. Ron Wyden.
And there are a lot of races to watch:
WA SEN: Washington Sen. Patty Murray has faced a tough and well-funded challenge from Republican Tiffany Smiley. Watch the margin here, as Republicans have grown more confident in their chances.
California, California, California: The most populous state in the country will start reporting its wave of House results – 52 House seats, more than half a dozen of which are competitive. Keep in mind that California often takes a very long time to report close congressional race results, so final numbers on how big (or small) a GOP wave is won't likely be known until the next day or even longer. Keep in mind that California uses a top-two primary system, so you could see multiple members of the same party on the general-election ballot.
Republican Kevin McCarthy, who is expected to be the next speaker of the House, at poll close will likely be announced as the winner of his contest.
There are House races with notable demographic and crossover district storylines: David Valadao has been a perennial Democratic target and this Central Valley – and heavily Latino – district (CA-22) has become even more Democratic. In the Orange County area, AAPI voters will be determinative in CA-45, for example, which pits Republican Michelle Steel, who is Korean American, against Democrat Jay Chen, who is Taiwanese American. There have been spats over identity here with Steel sending mailers accusing Chen of being a Communist sympathizer into a heavily Vietnamese community and Chen having made comments about Steel's accent.
OR GOV: To California's north, Oregon hasn't had a Republican governor in four decades, but Democrat Tina Kotek, who would be the first openly lesbian governor in the country, is facing a tougher campaign than expected from Republican candidate and state Rep. Christine Drazan. That's in large part because independent candidate Betsy Johnson – backed by billionaire Nike co-founder Phil Knight – has siphoned off moderate-voter support from Kotek.
Crime and homelessness are top of mind in the governor's race, and Portland Mayor Ted Wheeler hasn't issued an endorsement, saying he did not believe any candidate had produced thorough enough policies on addressing homelessness.
Copyright 2023 NPR. To see more, visit https://www.npr.org.
Domenico Montanaro is NPR's senior political editor/correspondent. Based in Washington, D.C., his work appears on air and online delivering analysis of the political climate in Washington and campaigns. He also helps edit political coverage.