Chicago - The T-shirts say it all: "A new hope. I was the change happened at Grant Park."

With presidential victory slipping further out of Republican John McCain's hands as the historic election night wore on Tuesday, Democrat Barack Obama was poised on the verge of a victory that could reshape the American political landscape.

The diverse sea of 65,000 Barack Obama supporters who had snagged tickets in Chicago queued for several kilometres around the historic park where the Democratic presidential candidate was holding an election eve rally late Tuesday after a nearly two-year long campaign and a tough general election fight against McCain.

Pedicab drivers offered to take those just arriving to the end of the line to shorten the wait. A white Cadillac painted with "Obama O8" and "Obamalac" in red, white and blue drew laughter and cheers from the crowd on an unseasonably warm night in the "Windy City."

Vendors hawked buttons, wrist bands and t-shirts featuring Obama as Superman and decrying the Republican ticket with the slogan "McCain-Palin same old Bushshit."

Hundreds of thousands of others crowded into the public area of the park, rushing toward giant televisions as CNN predicted the winner in each state.

When the key battleground of Pennsylvania was called for Obama, the crowd broke into cheers, with shouts of "We did it!"

Among the thousands of both blacks and whites, there was a sense of the historic moment with the possibility of the first African American president as well as relief at the end of the eight years of the George W Bush administration.

Susie Edmiaston, 59, and Randalyn Clark, 39, flew in from Fort Worth, Texas, to take part in the historic festivities and show that "there are Democrats in Texas," Bush's home state and one of the country's conservative strongholds.

"What colour will the sky be tomorrow?" Edmiaston asked as she reflected on the incoming election results, which were favouring Obama. "Something is going to be different tomorrow."

A likely Obama win was especially poignant for the African Americans in the crowd.

"It would make me feel like some real progress has been made since the civil rights movement," said Tiffany Gholar, 29.

But the tasks facing the next president, including a faltering economy and two wars, are daunting and there will be no easy fix, Gholar and other attendees admitted.

"It won't happen in four years," said Eric Shepherd, 24. (dpa)