Direct proof of use
The HMMWV was a widely used U.S. and coalition light tactical vehicle in the 2003 Iraq War. A U.S. military report from October 2004 said nearly 5,100 up-armored Humvees had already been delivered to Army and Marine Corps units in Iraq, with a Central Command requirement for 8,105 up-armored Humvees in Iraq.
Combat and patrol records document the vehicle in field use beyond procurement figures. DVIDS described U.S. soldiers in Iraq preparing for patrol, riding through streets in Humvees, and recovering after an IED strike in June 2007, while the Army Center of Military History described a June 2006 patrol near Musayyib that consisted of four up-armored Humvees and came under small-arms fire.
Sources: Up-Armored Vehicle Effort, IED Strikes Convoy on Patrol, Tip of the Spear
Timeline
By July 2004, the Army reported 18,656 armored and unarmored HMMWVs in CENTCOM's area of responsibility, and GAO described them as the most numerous U.S. military vehicles in that theater. The same GAO appendix described three armor-protection levels for HMMWVs in Iraq: factory up-armored vehicles, add-on armor kits, and field-improvised armor.
The armor push accelerated through 2004 and 2005. The October 2004 DVIDS/American Forces Press Service story recorded thousands of up-armored Humvees already delivered to Iraq and thousands of add-on kits installed on vehicles there; National Defense reported in October 2005 that the Army had shipped more than 10,000 armored Humvees to Iraq.
Sources: GAO Defense Logistics, Up-Armored Vehicle Effort, National Defense Armored Vehicles
Narrative
In Iraq, the HMMWV filled the coalition's everyday ground-mobility lane: convoy movement, patrol transport, troop carriage, and small-unit security tasks. Its size and maneuverability made it useful for urban and road movement, but the IED, grenade, and small-arms threat shifted the Iraq fleet toward up-armored M1114 vehicles and add-on armor packages.
The available sources separate vehicle fielding from combat incidents. DVIDS and GAO document the fielding and armor requirements, DVIDS video metadata documents Humvees in patrol and IED-recovery scenes in Iraq, and the Army Center of Military History provides a specific combat-patrol example in which up-armored Humvees carried a U.S. platoon element into Musayyib and turret gunners returned fire.
Sources: Up-Armored Vehicle Effort, GAO Defense Logistics, IED Strikes Convoy on Patrol, Tip of the Spear