Barack Obama is to be publicly sworn in as US president for second time.
Hundreds of thousands are expected in Washington for the event, which will feature music from Beyonce, parades, black tie balls and tight security.
They will crowd on to the Washington Mall to see the president take the oath of office on the steps of the Capitol.
Barack Obama was officially inaugurated in a small White House ceremony on Sunday, as the US Constitution requires the president be sworn in by January 20.
In the famous Blue Room, Barack Obama rested his hand on a Bible used for many years by his wife’s family and vowed “to preserve, protect and defend the Constitution of the United States”.
He will repeat those words at Monday’s public inauguration, in which he is also expected to use part of his address to outline his plans for the next four years.
Speaking at a reception for supporters late on Sunday, Barack Obama suggested he would dwell on the “common good” and the “goodness, the resilience, neighborliness, the patriotism” of Americans.
“What we are celebrating is not the election or the swearing-in of the president,” Barack Obama said.
“What we are doing is celebrating each other and celebrating this incredible nation that we call home.”
By the end of Monday, Barack Obama will have taken the oath four times – as many as President Franklin D Roosevelt.
Four years ago, Barack Obama had to repeat the oath privately to make sure all constitutional obligations were met after he tripped over the words.
Following Monday’s ceremony outside Congress, Barack Obama will have the traditional lunch with US lawmakers in the building’s Statuary Hall.
The president is then expected to follow the recent tradition of walking through the crowds for at least some of the way in the procession back to the White House.
Vice-President Joe Biden, who was also sworn in on Sunday, will repeat his oath publicly as well.
Thousands of workers and volunteers prepared Monday’s celebrations. White tents, trailers and generators are set up along the Washington Mall parade route, while nearby buildings have been adorned with red, white and blue bunting.
In 2009, nearly two million people crammed into Washington to witness President Barack Obama’s first inauguration.
Inauguration Day schedule:
11:30 EST : Official ceremony begins at the West Front of US Capitol
11:55 EST: Barack Obama is publicly sworn in as president by Chief Justice John Roberts
12:00 EST: Barack Obama delivers inaugural address
12:39 EST: Barack Obama signs nomination papers for his Cabinet
13:00 EST: Inaugural lunch in Statuary Hall at the US Capitol
14:36 EST: Inaugural parade on Pennsylvania Avenue, ending at the White House.