After a long, contentious campaign, Barack Obama won re-election as president of the United States, a victory that became clear after he clinched the necessary electoral votes in the state of Ohio.

In his hometown of Chicago, Obama declared, “We are an American family and we will rise or fall together as one nation and as one people.”

The president delivered his victory speech to throngs of supporters at McCormick Place convention center, not far from the Chicago’s Grant Park, the downtown venue where he claimed his historic victory four years ago.

Obama thanked thousands of supporters, many of whom had to work hard to earn their spots at the convention center rally.

Glen Kanwit of Evanston said he worked seven days a week focusing on what he called “voter protection,” which comprised of taking calls about the location of polling places and what volunteers needed to take. He came to McCormick Place late because he had worked phones well into Election Day.

“I like my president but we have to play on a fair playing field,” Kanwit said. “I’m going to keep this up after the election.”

In his concession speech, former Massachusetts Governor Mitt Romney congratulated the president and said, “I pray that he will be successful in guiding our nation.”

Congress remained split between the two major political parties, with Democrats maintaining the majority in the Senate. Their position was solidified after they wrested seats from the GOP in both Massachusetts and Indiana.

With almost 90 percent of the 435 House races called by The Associated Press, Republicans had won 224 seats and were leading in 15 more. For a majority in the chamber, a party must control 218 seats. By night’s end, Democrats had won 170 seats and were leading in 25 others.

Both parties managed to take at least some House seats previously held by the rival party.

In Illinois, Democrats had much to cheer about as their state’s stalwart wasn’t the only one to claim victory. Democrats picked up four U.S. Congressional seats in some of the most contentious — and expensive — races in the country.

In Chicago and the surrounding suburbs, however, voters were less than cheerful ahead of the results. Early Tuesday morning, tech troubles dogged the Chicago Board of Elections website, causing voters to scramble for basic information such as where they should cast ballots.

Also problematic: reports and claims of long lines and voting irregularities.

Chicagoan Laura Ormaza said she went to her assigned polling place with her voter registration card. But she said officials told her she was in the wrong precinct and wouldn’t let her vote.

“I shouldn’t have to yell and argue and fight with someone for my right to vote,” Ormaza said. “It’s absurd. It’s unheard of.”

Ormaza said she was eventually allowed to cast her ballot, but she was concerned for other voters who were turned away or were not willing to fight.

Polling snafus aside, races in Illinois were tight and closely watched.

In Illinois’ 8th Congressional District, Democrat and Iraq War veteran Tammy Duckworth beat tea party darling Joe Walsh.

The race attracted significant media attention — and PAC dollars — from beyond the state’s borders.

“Together, we bring a new attitude to Washington,” Duckworth told supporters at her celebration rally. “On my first day, I will remind Congress we are here to serve the people.”

Duckworth was aided by new congressional boundaries, which the Illinois General Assembly redrew to include more minority voters.

One-term U.S. Rep. Bob Dold conceded to Democrat Brad Schneider in an extremely tight race for Illinois’ 10th District, which encompasses many of Chicago’s northern suburbs. Polls had consistently shown the race was a toss-up, though later polls predicted a Dold victory.

In the 11th District, Democrat Bill Foster defeated Republican congresswoman Judy Biggert, who’d been the incumbent in the 13 District. The match was inaugurated after Illinois Democrats redrew district boundaries and forced Biggert into a match against a strong opponent. Still, Foster’s final lead was far larger than expected — 58 percent to Biggert’s 42.

In the 13th District, Republican Rodney Davis beat Democrat David Gill. The Republican incumbent Tim Johnson announced he would not seek re-election.

In Illinois’ newly drawn 17th Congressional District, Democrat Cheri Bustos defeated Republican Congressman Bobby Schilling.

That matchup had been one of the most closely watched in Illinois, as Democrats had considered it an opportunity to pick up a seat in their fight to regain control of the House. Republicans also poured in big money to defend it.

There were also some unorthodox victories in Illinois that are sure to garner commentary from Illinoisans and outsiders alike.

For one, longtime U.S. Rep. Jesse Jackson Jr. handily won another term in the 2nd congressional district, despite being on medical leave since June. His office has said he is suffering from bipolar disorder and gastrointestinal issues, and is being treated at the Mayo Clinic.

“Once the Doctors approve my return to work, I will continue to be the progressive fighter you have known for years. My family and I are grateful for your many heartfelt prayers and kind thoughts. I continue to feel better everyday and look forward to serving you,” Jackson said in a statement.

On the state level, Democrats retained control of the Legislature, with a potentially embarrassing victory involving Rep. Derrick Smith, who had been expelled after his indictment for bribery charges. He won his seat, despite the fact that major players in his own party — including Illinois Secretary of State Jesse White — actively campaigned against him. They had thrown support behind Lance Tyson, a third-party candidate.

Illinois voters also rejected a proposed amendment to the state constitution that would have required a three-fifths vote ― instead of a simple majority ― for any public body to increase public pension benefits.

– Scott Kanowsky, Tony Arnold, Lauren Choolijian and the Associated Press contributed to this report.