City officials say downtown businesses should consider letting their employees go home early on Election Day.
It now appears tickets will be required to get into Obama's event. But many who want to be a part of next week's rally are still expected to flock to the park.
"There will be a lot of people who want to come down and celebrate, and we hope it's a million or more," Daley said.
If what the mayor hopes for actually happens, Obama's election night speech will attract many more people than the 70,000 city officials say can fit into the southernmost part of Grant Park known as Hutchinson Field. Stages, camera platforms and tents are being set up there inside a fence surrounding what by election night, will be one of the most secured outdoor areas in the United States.
The mayor said he expects that more than ten times as many people will gather elsewhere downtown and along the lakefront for what Daley called "a festival."
"It's going to be called a celebration. People coming down want to celebrate, and that's what the feeling I have for this huge event is going to take place next Tuesday," Daley said.
Chicago Police Superintendent Jody Weis, whose currently undermanned department would have to control crowds inside as well as outside the perimeter, appeared surprised at the mayor's prediction of one million.
"I was at meetings all day yesterday concerning that, and I didn't think anyone would have an exact number," Weis said.
Huge crowds and the additional Secret Service effort they require have become a staple of Obama's presidential campaign. The mayor has put a $2 million price tag on the election night event and said last week the campaign has promised to pay "every penny of it" because of the city's financial crisis.
As for maintaining public safety that night, the mayor said Chicago's police and fire departments understand the challenge.
"Well, you have to be concerned when you get one million people, that's a lot of people. You better be concerned," Daley said.
In an e-mail Tuesday, the Obama campaign invited Illinois supporters to sign up for an un-announced number of tickets to the speech inside the secured Hutchinson Field.
Officials in the Obama campaign say they are anticipating they will get a heavy response for tickets. They are getting prepared by taking down information from interested volunteers. Once they determine the amount of tickets available and how they will be giving them out, those people that are registered will be notified.
Those given the opportunity for tickets either registered with the campaign some time during the election off their web site, participating in a phone bank or volunteered.