Democrats have controlled the Senate for the last eight years, but in today’s midterm elections, the GOP is hoping to collect enough numbers to tip the scale. With a number of extremely close Senate races happening all over the country today, every vote will count.

But with polling numbers this close, it’s likely that we won’t know who controls the Senate by the end of day, or even months later, due to the possibility of senate runoffs in Louisiana and Georgia. 

“It’s entirely possible Election Day will turn into Election Two Months, and go all the way to January,” Nathan Gonzales, deputy editor of the Rothenberg Political Report, told the Wall Street Journal.

Republicans will need to gain six net seats to gain the Senate majority, since the current Senate is divided by 53 Democrats to 45 Republicans, including two independents that vote with Democrats. 

Here are the top 10 Senate races to track tonight and over the next few weeks: 

1. Louisiana: Democratic incumbent Mary Landrieu has served as a senator in Louisiana for three terms. Today, she faces Republican challenger Bill Cassidy. Add Republican candidate Rob Manness to the mix - who, despite not being favored to win, has the ability to ensure that neither Landrieu nor Cassidy receive more than 50 percent of the votes.

This would result in the need for a runoff vote, which would take place on Dec. 6. To prepare for the extended midterm season, Democrats and Republicans have started reserving budget allocations to more advertising, and planned staff deployments for both Louisiana and Georgia.

“There will be a huge amount of money being raised. There will be a ton of advertising for people who have already been subjected to a ton of advertising,” said Robert Shrum, a professor and chair of the political science department at USC.  “It’ll be like the mini midterm.”

2. Georgia: Georgia is the second state with a high probability for a runoff election, as Democrat Michelle Nunn and Republican David Perdue battle for an open Senate seat.

A NBC/Marist poll released Sunday shows Perdue up by four percentage points over Nunn. With the margin of error plus or minus four percentage points, though, the candidates are statistically tied. Should this remain the case after today’s election, the runoff vote wouldn’t happen until Jan. 6.

Because of this dead heat, “there’s about an 80% chance a runoff vote will happen in Georgia,” he said. 

3. Alaska: Alaska is another state from which we will be awaiting a decision after tonight’s results are announced around the country. The state’s polls don’t close until 1 a.m. EST, and Alaska allows 10 days for absentee ballots. They won’t officially announce results until 15 days after the election.

Polls have consistently shown Democratic incumbent Sen. Mark Begich and his Republican opponent Dan Sullivan locked in a close race. “The Alaska Senate race is even tighter than the one in Colorado, with Dan Sullivan leading Mark Begich just 46/45 with the full field and 47/46 in a head to head contest,” Public Policy Polling wrote in a statement on Monday. 

4. Kansas: As three-term incumbent Republican Sen. Pat Roberts tries to maintain his seat in Kansas, independent challenger Greg Orman poses a strong threat. A poll released Monday by Public Policy Polling revealed that Orman leads Roberts 47 to 46 percent. Libertarian Randall Batson saw support from 3 percent of respondents, and another four percent were undecided.

“Roberts’ [approval spread] is 34/54. Usually politicians with those kinds of approval ratings are doomed for re-election but Kansas’ deep red hue is still giving them a shot,” the firm stated in a statement that accompanied the poll. 

5. Kentucky: It’s widely expected that Senate Minority Leader Mitch McConnell will hold the seat in Kentucky. But eyes will be on Kentucky Secretary of State Alison Grimes to see if she has the power to tip the state towards Democrats. Public Policy's poll released on Monday showed that McConnell leads Grimes 50/42, with Libertarian David Patters receiving 3 percent of respondents’ support. In a head to head match up, Public Policy reported that McConnell's lead is 53/44.

UPDATE 4:01 PM: News outlets have projected that McConnell has won re-election, with 55 percent of the vote to Grimes' 41 percent.

6. New Hampshire: While New Hampshire is typically a blue state, polls show that the race between Democratic incumbent Sen. Jeanne Shaheen and Republican challenger Scott Brown could go either way. According to Shrum, the earliest indication if Democrats can maintain control of the Senate will be the results from New Hampshire and North Carolina.

“The question is, will Democrats hold the states they are supposed to hold?” he said. “I think Shaheen will win the odds are that Hagan will win, but its possible that either or both could loose. If both do lose, then the Democrats I think have no chance to hold onto their senate majority.”

While a WMUR poll released Sunday revealed that Shaheen holds the lead on Brown, a New England College poll showed Brown with a one-point lead on Shaheen. Both results amount to a statistical tie, as the leads fall within the polls' margin of error. 

7. North Carolina: The Tar Heel state is another state where Democrats are clinging onto their Senate seats. Democratic incumbent Kay Hagan has consistently led in the polls over state House Speaker Thom Tillis, but only in low-single digits, according to PBS Newshour.

It has also been the most expensive senate race in U.S. history. Money spent or committed in the race is expected to top $103 million, according to public records. “It’s a stunning number, and it tells you two things,” Larry Sabato, a University of Virginia political scientist, told the Charlotte Observer. “That campaign finance is completely out of anybody’s control and North Carolina is a premier swing state."

8. Iowa: Iowa is playing its usual role as another swing state, and will be another state to watch as poll results show a dead heat between Democrat Bruce Braley and Republican Jon Ernst. “This is race is closer than it should be,” said Dan Schnur, executive director of the Jesse M. Unruh Institute of Politics. “Brarley was a strong early favorite and made a couple of errors that cost him a lot of support.”

A Quinnipiac University poll published Monday showed the two candidates tied at 47 percent among likely voters. The Iowa Secretary of State reported they had received over 455,000 absentee ballots by Monday, representing the strongest early voter turnout in a midterm election in Iowa history.  

Of the absentee ballots collected, Democrats turned in close to 184,000 and Republicans turned in nearly 176,000. 95,398 were no-party voters; 475 were libertarian and 215 were Green party voters. 

10. Arkansas: Another state, another Democrat incumbent under threat. Two-term Sen. Mark Pryor, who has been leaning further to the right since his first election, will face Republican challenger Tom Cotton. Public Policy Polling released on Saturday survey results that show Cotton leading 49/41 over Pryor.

The results of the Senate race could make Arkansas another swing state for the next presidential election. It is, however, important to note that Obama lost Arkansas by a notable margin both in 2008 and 2012, said Schnur. “On one hand, every Senate seat counts exactly the same amount, but there are a few states that have greater importance than just statistics,” he said.

Reach Staff Reporter Emily Goldberg here.