With Democrats in control of the White House and Congress, Republicans face profound questions about what the party stands for without Donald Trump in charge.
Trump, who departed the White House shortly after 14:00 CET with his wife, Melania, said it had been "a great honour, the honour of a lifetime" to serve as president.
Melania Trump said the past four years have been "unforgettable" and urged Americans to "be passionate in everything you do but always remember that violence is never the answer and will never be justified".
President-elect Joe Biden will be holding an "indoguration" this year for his rescue pups.
From cabinet appointments to coronavirus legislation, Biden's ability to enact his agenda hinged on the outcome of Georgia's two Senate run-offs.
Congress has approved a $900 billion stimulus package but President Trump is blocking it.
Trump pardoned more than two dozen people, including former campaign chairman Paul Manafort and Charles Kushner, the father of his son-in-law.
"A voice like mine has never been a Cabinet secretary or at the head of the Department of Interior," Haaland said, vowing to be "fierce".
The US Senate will begin confirmation hearings for Donald Trump's nominee to the Supreme Court, a mere three weeks before the presidential election.
The app, owned by ByteDance, a private Chinese company, has come under scrutiny in Australia after Donald Trump announced plans for a possible ban in the United States.
The pilgrims built a new life in Plymouth, Massachusets, in 1620. The area's original inhabitants paid a heavy price.