Senate watchers should get ready for a long election night.

Control of the Senate might well be in flux past Tuesday night, as states take days to count absentee ballots and the two Senate races in Georgia could head to runoffs.

Some states with contested Senate races have already been counting absentee, mail-in or early votes (Arizona started two weeks ago) and others may not even open those envelopes for a week (looking at you, Alaska).

The first polls in the country will close a 6 p.m. Eastern Time across much of Kentucky. The cascade really begins at 7 p.m. Eastern, when polls close in western Kentucky and across Georgia, South Carolina and Virginia.

Six years ago, when these same Senate seats were up, the fact that Virginia Democrat Mark Warner’s reelection was not called immediately proved a harbinger of good news for Senate Republicans. Warner’s race is not expected to be close this year, and it will be a surprise if he is not the first candidate declared victorious.

Here’s what to look for as polls close in the 14 states featuring competitive Senate races. All times are Eastern.

7 p.m. Georgia, Kentucky and South Carolina 

Absentee ballots in Georgia are due by Election Day, but results in close races may still take a while to sort out.  

The state is hosting two competitive Senate races. If no candidate wins a majority of the vote, the top two vote-getters will head to a Jan. 5 runoff. Runoffs are possible in both contests, with recent polls showing GOP Sen. David Perdue and Democrat Jon Ossoff both falling short of the 50 percent threshold. Inside Elections with Nathan L. Gonzales rates Perdue’s race a Toss-up.

The other race is a special election to serve the final two years of former GOP Sen. Johnny Isakson’s term and features candidates of all parties competing on the same ballot.

Democratic pastor Raphael Warnock is expected to advance to the January runoff. But GOP Sen. Kelly Loeffler, who was appointed to the seat after Isakson resigned due to health issues, is locked in a battle for second place with GOP Rep. Doug Collins. Inside Elections rates the special election Tilt Republican.

Polls also close at 7 p.m. in two states where high-ranking Republicans face well-funded Democratic opponents. 

In Kentucky, Senate Majority Leader Mitch McConnell takes on Marine veteran Amy McGrath in a race Inside Elections rates Solid Republican. Some polls close at 6 p.m. Eastern time, but Kentucky covers two time zones. The New York Times reported that counties are supposed to report election results by midnight. But absentee ballots postmarked by Tuesday will also be counted if they are received by Friday.

South Carolina Democrat Jaime Harrison has shattered fundraising records in his race against Senate Judiciary Chairman Lindsey Graham, which Inside Elections rates Tilt Republican. Absentee ballots must be received by the time polls close. 

7:30 p.m. North Carolina 

Initial results from votes cast early and by mail are expected within the first hour after the polls close in North Carolina, where GOP Sen. Thom Tillis faces former state Sen. Cal Cunningham. Inside Elections rates the race Tilt Democratic.

Results from ballots cast in person on Election Day are expected to be reported between 8:30 p.m. and 1 a.m. Absentee ballots postmarked by Election Day will be counted if they are received by Nov. 12.

8 p.m. Alabama and Maine

Alabama Democrat Doug Jones, the most vulnerable senator running for reelection, may learn his fate Tuesday. The Alabama secretary of state has pledged that unofficial results will be reported on election night. Absentee ballots are due by Tuesday, and officials can start processing them at 7 a.m. Jones faces former Auburn University football coach Tommy Tuberville in a race Inside Elections rates Lean Republican.

Absentee ballots are also due Tuesday in Maine, where GOP Sen. Susan Collins faces a competitive race against Democrat Sara Gideon, the state House speaker. Inside Elections rates the race Tilt Democratic. 

But results could still take a while, thanks to the state’s ranked-choice voting system, where voters note their second- and third-choice candidates. If no candidate wins more than 50 percent of the vote, the person in last place is eliminated and his or her supporters’ votes are reallocated to their second choice. The rounds continue until a candidate receives a majority of the vote. In 2018, it took a week to learn the results of Maine’s 2nd District contest due to the ranked-choice system.

9 p.m. Arizona, Colorado, Kansas, Michigan and Texas 

In 2018, it took six days before it was clear that Democrat Kyrsten Sinema had defeated Republican Martha McSally in the Arizona Senate race. After that loss, McSally was appointed to the state’s other seat, which opened after the death of Republican Sen. John McCain. McSally is now in a competitive race against Democrat Mark Kelly to serve the last two years of McCain’s term. Inside Elections rates the race Tilt Democratic.

Unlike in 2018, officials were allowed to start counting mail ballots two weeks ago, thanks to a new state law. But Arizona officials have cautioned that the winners may still not be known on election night.

In Colorado, where GOP Sen. Cory Gardner faces former Democratic Gov. John Hickenlooper, results may be clear late Tuesday or early Wednesday, according to The New York Times. Colorado is among a handful of states that conducted elections entirely by mail prior to the pandemic, and ballots are due by Election Day. Inside Elections rates the Senate race Lean Democratic.

Most polls in Kansas close by 8 p.m., but it’s crucial to wait until polls close an hour later in the rural, western part of the state, a GOP stronghold. That area will likely be friendlier to GOP Rep. Roger Marshall, who is locked in a competitive Senate race against Democratic state Sen. Barbara Bollier, a former Republican. Inside Elections rates the contest Tilt Republican. Absentee ballots postmarked by Tuesday will be counted if received over the next three days. 

Michigan is the only other state where Democrats are on defense, with Sen. Gary Peters facing Republican Army veteran John James in a race Inside Elections rates Lean Democratic.

Absentee ballots are due Tuesday, and early ballots could be processed, but not counted, before Election Day. Secretary of State Jocelyn Benson cautioned that unofficial results may not be clear for a few days.

Most Texas polls close at 8 p.m., but polls in its two westernmost counties, which fall in a different time zone, won’t close until an hour later. Absentee ballots can be counted if they’re received by Wednesday, while military ballots are due by Nov. 9. Texas has been more competitive at the presidential level than in the Senate race, where Democratic Air Force veteran MJ Hegar is taking on GOP Sen. John Cornyn in a contest rated Lean Republican.

10 p.m. Iowa and Montana 

Both of these states feature Toss-up Senate races, with Iowa GOP incumbent Joni Ernst facing real estate executive Theresa Greenfield, and Montana Republican Sen. Steve Daines looking to fend off Gov. Steve Bullock. 

In Iowa, absentee ballot results may be reported first, but officials will also count ballots that arrive by Nov. 9. Absentee ballots in Montana are due by Election Day. 

Midnight: Alaska 

GOP Sen. Dan Sullivan’s contest against Al Gross, an independent backed by national Democrats, could be decided late, and not only because of the state’s geographic location.

People who voted early or by absentee ballot are expected to see their votes tabulated on election night along with those from in-person Election Day voters.

But ballots cast from Oct. 30 onward, other than the in-person Election Day voters, won’t be counted for a week. Alaska allows ballots postmarked by Election Day and received over the next 10 days to be counted.