WASHINGTON — A vast, excited crowd of more than 1 million bore witness Tuesday to a transfer of American power like none before it. The blare of regal trumpets and thunder of cannon were familiar. The transition from Republican to Democrat, and gray hair to dark, had happened before.

This, however, was white to black, a shattering of racial barriers finally made complete when Barack Obama made it through a bumbled oath-taking, delivered a momentous-by-definition speech and got back to being his unflappable self.

The Democrat who charged onto the national scene saying this was not a nation of red states and blue states, but the United States, became president while wearing a red tie, the Republican color.

Republican George W. Bush, president no more, wore a blue tie, the Democratic color. They embraced at the Capitol and walked out together.

“Everybody is behind him,” said Mikki Hill, 26, who traveled from Winston-Salem, N.C., and marveled at the multiracial multitudes. “Everybody’s come from as far as the Earth is wide.”

So it seemed on a day when change and continuity marched together in a spectacle of pageantry and raw emotion.

A couple of hours after being sworn in, Obama and his wife, Michelle, got out of their armored limousine bearing the license plate USA 1 and strolled together down the middle of Pennsylvania Avenue, holding hands and waving during the spirited inaugural parade. People along the packed parade route screeched in greeting.

Some 13,000 marchers from 50 states paraded along the avenue, passing the Obamas in their enclosed reviewing stand in front of the White House. The sun was falling by then and many watching the parade had been there in the biting cold since dawn or earlier.

“I can’t feel my butt,” said Jarita Moore, 28, of Alexandria, Va. “My legs are numb. I got a picture of him in the car.”

The racial milestone lent a deeply personal dimension for many in the crowds as well as a historical landmark for all.

“I’ve been real emotional all morning thinking about my grandmother and the heroes whose shoulders we stand on,” said Lyshundria Houston, 34, here from Memphis, after more than 20 hours of travel. Houston, who is black, said: “They’d be so proud.”

Energized by the moment, hordes clogged the scene, enduring below-freezing temperatures. Starting before dawn, with the Capitol bathed in lights, they streamed from jammed subway stations and thronged past parked buses, emergency vehicles and street vendors to Pennsylvania Avenue and the National Mall.

Ticket holders approaching the inaugural site filed through security sweeps in lines coiled like cinnamon rolls.

They cheered dignitaries as they came on to the inaugural stand at the Capitol.