The battalion redeployed back to Fort Carson in March 2004. As a result of the transformation of the brigade to the modular concept, elements of the battalion were changed to a cavalry squadron, the 2nd Squadron, 9th Cavalry Regiment in November 2004. 1st Battalion, 12th Infantry Regiment was reactivated at Fort Hood as part of the 4th BCT, 4th Infantry Division and deployed to Baghdad, Iraq, in fall of 2005 in support of Operation Iraqi Freedom. It was replaced in the fall of 2006 by the 2nd BCT, 2nd Infantry Division from Fort Carson. This unit was temporarily assigned to 1st Cavalry Division to which the 2d Battalion, 12th Infantry Regiment was attached until February 2007 when the 4th BCT, 1st Infantry Division was assigned tactical control of Baghdad. On 6 April 2015 the 1st and 2nd Battalions, 12th Infantry Regiment were re-flagged under the 2nd IBCT, 4th Infantry Division, Fort Carson, Colorado. In December 2001, Companies B and C of the 1st Battalion deployed to Kuwait in support of Intrinsic Action 01-02 and later in support of Operation Enduring Freedom. Elements of other units from within the 3d BCT, 4th Infantry Division made up the remainder of Task Force 1-12. The task force redeployed to Fort Carson in May 2002. In May 2009, 1st and 2nd Battalions, 12th Infantry Regiment, 4BCT, 4th Infantry Division, deployed to Afghanistan in support of Operation Enduring Freedom X. 1st Battalion was based in the Arghandab River Valley, west of Kandahar City, for the latter eight months of the deployment. Task Force 1-12's area of responsibility was referred to as the "Heart of Darkness" due to its significance as the birthplace of the Taliban, and also due to the inherent complexity of their mission. Much of their fighting was conducted in notoriously dense grape fields, which provided excellent concealment for insurgent forces. The 2nd Battalion was based in the Pech River Valley, Kunar Province, home to the Korengal, Waygal, Shuriak, and Wata Pour Valleys. During its time in the Pech Valley, the 2nd Battalion saw heavy fighting throughout their area of responsibility at the foothills of the Hindu Kush mountains. In June 2010, Task Force 1-12 and Lethal Warrior (2-12), 4th BCT, 4 ID redeployed to Fort Carson, Colorado, after 12 months in Afghanistan.