U.S. forces have handed Joint Base Balad, which was once one of the world's busiest airports and housed some 36,000 personnel, over to Iraqi control, a US military spokesman said on Wednesday.
"We handed over Joint Base Balad (JBB) yesterday," the spokesman said, adding that at its peak, the base to the north of Baghdadhoused "28,000 uniformed personnel and 8,000 civilian contractors."
"It was the second-largest base (for US forces in Iraq) in terms of personnel," the spokesman said.
Only the Victory Base Complex on Baghdad's outskirts once housed more -- an estimated 100,000-plus people, some 42,000 of whom were military personnel and over 65,000 others who were contractors, according to Lieutenant Colonel Jerry Brooks, the command historian for United States Forces - Iraq.
Balad had "27,500 landings and take-offs a month" in 2006, making it one of the world's busiest airports, the spokesman said.
The 332nd Air Expeditionary Wing was the last unit to leave JBB, which occupied 25 square kilometres (nine square miles) and had a 20-kilometre (12-mile) security perimeter.
"Balad was a Level I trauma centre which boasted a 98-percent survival rate for wounded Americans and Iraqis alike," the spokesman said.
All of the roughly 31,000 US military personnel in Iraq are to depart the country by year's end, after negotiations between Baghdad and Washington on a post-2011 US military training mission broke down.
Eleven US bases remain to be handed over, according to the spokesman.