Bush and his wife Laura watched new president Barack Obama take the oath of office on the steps of the US Capitol, before departing.
They were flown from the city to Andrews Air Force Base, from where they will take the former Air Force One to Crawford, Texas.
Many of the crowds gathered to watch Obama\’s inauguration waved to the helicopter as it took Bush on his final sweep over The Mall and Pennsylvania Avenue.
For the first time since January 20, 2001, his helicopter was not called Marine One and the plane was not Air Force One – both call signs reserved for the US president in office.
Bush\’s departure brought the curtain down on eight turbulent years that end with the outgoing president leaving unfinished wars in Afghanistan and Iraq and the worst economic crisis since the Great Depression of the 1930s.
Over his term\’s final months, the unpopular leader worked to convince the US public and future historians that he should get credit for guiding the country through a rocky time marked by the September 11, 2001 terrorist attacks.
Earlier, Bush hosted his successor Obama for a private coffee before they climbed aboard the armoured limousine taking them to the Democrat\’s inauguration.
The outgoing leader followed the custom of leaving a note for the incoming president in the top drawer of the massive Resolute Desk – made from the timbers of the British ship of the same name – in the Oval office.
Bush spokeswoman Dana Perino declined to give details of the confidential letter, but said he focused on “the fabulous new chapter president-elect Obama is about to start, and that he wishes him the very best”.
In his last hours before leaving office, Bush spoke by telephone with US Secretary of State Condoleezza Rice, national security adviser Stephen Hadley, and former White House chief of staff Andy Card, Perino told reporters.
The outgoing president also took a final walk through the Oval Office, thanked staff, and “gave me a big kiss on the forehead, which I will never forget”, said the spokeswoman.