Get in line.

That’s what thousands of campus visitors will hear on Sunday when they try to get onto the Oval to see President Barack Obama rally to keep Democrats in power in the state and in Washington.

Although planners call the rally a public event — it won’t require a ticket — police barricades will seal the Oval from the public unless they line up at the public entrance between the William Oxley Thompson Library and Mirror Lake.

And with a growing list of big-name appearances, including a recently announced opening performance by John Legend, organizers warn that the line could get long — really long.

“There was a line a mile long at Wisconsin,” said Micah Kamrass, president of Undergraduate Student Government at Ohio State, referring to Obama’s visit to the University of Wisconsin in late September.

That rally, the largest rally featuring Obama since his election, drew 26,500 people and a 1.1-mile line, according to police at the University of Wisconsin.

But if the leader of OSU’s College Democrats gets his way, Ohio will beat that record on Sunday, a day after the Buckeyes face Wisconsin in Madison, Wis.

“It would be really nice to beat them twice in one weekend,” said Matt Caffey, whose organization lobbied to bring Obama to campus.

His advice for students is to line up early and be ready for restrictions similar to airport security, including metal detectors.

“Wear good shoes and make sure you bring plenty of water that day because it’s going to be a lot of standing,” he said. “But it’s going to be worth it.”

Officials from the Democratic National Committee said visitors can’t bring signs, large bags or umbrellas into the rally but can bring cameras and phones. Christina Tamburro, a spokeswoman for the DNC, said security officers will inspect electronics.

OSU spokeswoman Shelly Hoffman said the DNC paid $10,000 to rent the Oval for the event, about the same the group paid to rent space in Wisconsin.

Although police haven’t determined which buildings will be closed for the rally or for how long, Chief Paul Denton of OSU Police said some buildings around the Oval likely will be off-limits and that police will cut off access to the Oval from the William Oxley Thompson Library.

According to the DNC, visitors will be able to park at the Ohio Stadium and St. John Arena parking lots on a first-come, first-served basis.

Some weekend workers at OSU will have to change their plans because of the extra traffic, organizers said.

“There are definitely going to be some changes and adjustments people have to make,” Kamrass said. “It will certainly be an inconvenience for some.”

But he said Sunday is the best day to bring the president to campus because it won’t disrupt classes or student group gatherings.

Denton said drivers near campus should expect closed or restricted roads between 17th and 19th avenues, and on Neil Avenue, north of 12th Avenue.

His department will work with the Secret Service and local agencies to keep the crowd safe Sunday. And although he said the event will be exciting, it’s nothing new for campus police.

“It’s not the first time a president has come to campus,” he said. “Our staff train for these kind of events.”

Alex Hampel contributed as a reporter to this story.