Trump to leave White House for Florida before ceremony
Joe Biden is to be sworn in as the 46th US president just before 17:00 GMT in Washington.
Vice-President-elect Kamala Harris will take the oath of office alongside him - the first woman to hold that position.
Some 25,000 troops will guard the inauguration ceremony after a deadly riot at the Capitol earlier this month
Donald Trump will not attend his successor's inauguration - only the fourth president not to do so.
He will leave the White House for the last time, bound for Florida, at around 13:00 GMT.
When President Trump hosts a farewell ceremony for himself at Andrews Air Force Base on Wednesday morning, one man will be notable by his absence - his Vice-President Mike Pence.
Instead Pence will be attending the inauguration of Joe Biden and Kamala Harris.
His aides told the Washington Post that it would it would be "logistically challenging for the vice-president to do both."
Pence has also shared a series of pictures in a farewell tweet - none of them featuring Trump.
Biden to act on race, immigration and LGBT rights.
As part of the huge package of executive action announced a short time ago, President-elect Biden's team say he will also take action to address equality and immigration:
He will issue an executive order to address racial equity in federal policy-making and programs, in a measure aimed to help root out systemic racism. This will also directly undo Trump administration policies, including an order which saw diversity and inclusion training limited.
He will sign an executive action to end President Trump's controversial travel ban which restricted US entry from some Muslim-majority nations.
He will order a stop to all border wall construction on the US border with Mexico, pending a review of the legality of funding being used by the previous administration.
He will sign an executive order revoking a Trump plan to exclude undocumented migrants from the census and sign a memo to help fortify protections for "dreamers" - a scheme that shields young undocumented immigrants from deportation.
He will also sign an executive order to help prevent and combat discrimination - including in the workplace - on the basis of gender identity and sexual orientation.
Kamala Harris savoured the moment she became the first woman, and the first black and Asian-American person, to be vice-president-elect, with a very hearty laugh.
In a video posted to her social media she shares the news with President-elect Joe Biden: "We did it, we did it Joe. You're going to be the next president of the United States!"
Her words are about him but the history of the moment is hers.
Just over a year ago, as the senator from California hoping to win the Democratic nomination for presidency, she launched a potent attack on Joe Biden over race during a debate. Many thought it inflicted a serious blow on his ambitions.
But by the end of the year her campaign was dead and it was Mr Biden who returned the 56-year-old to the national spotlight by putting her on his ticket.