The last US combat brigade in Iraq has left the country, seven years after the US-led invasion.
The 4th Stryker Brigade, 2nd Infantry Division, began crossing by land into Kuwait in the early hours of Thursday, a military spokesman said.
Some 50,000 US troops will remain until the end of 2011 to advise Iraqi forces and protect US interests.
A further 6,000 support troops will be in Iraq until the end of the month, when US combat operations will end.
Stryker Brigade's personnel drove out of Iraq in a convoy of armoured vehicles.
The journey along potentially hostile desert roads had been carefully planned for weeks.
"The last one crossed [into Kuwait] at around 0600 (0300 GMT) this morning," Lieutenant Colonel Eric Bloom said.
The US military restricted journalists embedded with the brigade from reporting on its movements until they were almost at the border.
After crossing the border, US troops told journalists of their relief at leaving Iraq.
"It's just a whole bunch of stress just off my shoulders, but it feels good to be in Kuwait, about to head home," Troy Danahy said.
"Best part of getting back to Kuwait? One, I know no one else will get hurt, and two, I'm going home," Timothy Berrenar said.
State Department spokesman PJ Crowley said the US involvement in Iraq was far from over, but that it would be less intrusive and more civilian focused.
"We are ending the war... but we are not ending our work in Iraq. We have a long-term commitment to Iraq," he told MSNBC.
Mr Crowley said the US had a trillion-dollar investment to protect in the country and wanted to honour the memory of the 4,415 US troops who lost their lives in the conflict.
At one point, the US had 150,000 troops in Iraq.
The independent monitoring group Iraq Body Count put the number of civilian deaths since the invasion at between 97,196 and 106,071.
The BBC's Jane O'Brien in Washington says the brigade's departure is a significant step.
The 50,000 soldiers who will remain will be armed, but will only use their weapons in self-defence or at the request of the Iraqi government.