The 12th Infantry Regiment is one of the oldest and most decorated units of the United States Army. The 12th Regiment has fought in seven wars from the Civil War to the Global War on Terrorism and has been awarded four Presidential Unit Citations, five Valorous Unit Awards and the Belgian Fourragere.

Civil War
Less than a month after the first shots of the Civil War were fired at Fort Sumter in South Carolina, the 12th Infantry Regiment was reconstituted 3 May 1861 in the Regular Army as the 1st Battalion, 12th Infantry
Indian Wars
The Battalion was reorganized and redesignated as the 12th Infantry Regiment on 7 December 1866. In the 1870s, the Regiment took part in three campaigns of the Indian Wars

Spanish-American War and Philippine-American War
During the Spanish–American War, the 12th Infantry was sent to Cuba, in June 1898, and participated in the storming of the Spanish fortress in the Battle of El Caney, where the 12th had the distinction of capturing the Spanish colors.

Garrison Duty
On 17 December 1917 the 12th Infantry was assigned to the 8th Division, but was not sent overseas in World War I.

World War II
The 12th Infantry Regiment was reorganized as a motorized infantry regiment on 29 September 1942. Less than a year later, on 1 August 1943, the 12th was reorganized as a standard infantry regiment when the 4th Division was converted from motorized to dismounted infantry


Cold War
On 15 July 1947, the 12th Infantry Regiment was reactivated as a training regiment when 4th Infantry Division was given the mission of basic training at Fort Ord, California. In July 1951, the 4th Division was returned to line status and rotated to Germany as part of Operation Gyroscope. In 1956, the Division returned to the United States and was stationed at Fort Lewis, Washington.

Vietnam
The three 12th Infantry battalions deployed to Vietnam with the 4th Division from August through October 1966. The 3rd Brigade, 4th Division, to which the 2nd Battalion, 12th Infantry was assigned, set up base camp at Dau Tieng in III Corps while the rest of the 4th Division was assigned to the Vietnamese Highlands in II Corps alongside the 3rd Brigade of the 25th Division which had arrived in December 1965. On 1 August 1967, the two divisions swapped 3rd Brigades. Subsequently, the 2nd Battalion, 12th Infantry served with the 25th through 10 of the Battalion's 11 Vietnam campaigns and received the Presidential Unit Citation for gallantry in action at Suoi Tre. As part of the U.S. draw-down, the 2nd Battalion, 12th Infantry was returned to Fort Lewis, WA, and inactivated on 17 April 1971.


Operation Seam Signal
The 1st Battalion, 12th Infantry Regiment "Warriors" of the 4th Infantry Division deployed from 29 August 1994 - 25 February 1995 to Guantanamo Bay, Cuba in support of Joint Task Force 160 to provide refugee camp security at Camp Alpha, Camp Bravo, Camp Golf, Camp Mike, Camp Quebec, Camp Romeo, Camp Sierra, and Camp X-Ray

Operation Iraqi Freedom
The 1st Battalion, 12th Infantry Regiment was formerly assigned to the 3d Brigade Combat Team of the U.S. 4th Infantry Division at Fort Carson and deployed with the 3d BCT in March 2003 in support of Operation Iraqi Freedom I. 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 2d BCT, 2d 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. 1st and 2d Battalions, 12th Infantry Regiment are currently assigned to 4th BCT, 4th Infantry Division, Fort Carson,

Operation Enduring Freedom
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 2d Battalions, 12th Infantry Regiment, 4BCT, 4ID, deployed to Afghanistan in support of Operation Enduring Freedom. 1st Battalion was based in the Arghandab River valley, west of Kandahar city for the latter eight months of the deployment. Referred to as the "Heart of Darkness" due to it having been the birth place of the Taliban regime, and also due to the complexity of the mission in their Area of Operations. Much of their fighting was conducted in notoriously dense grapefields, which provided excellent cover and 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 2d Battalion saw heavy fighting throughout the area. In June 2010, Task Force 1-12 and Lethal Warrior(2-12), 4th BCT, 4th Infantry Division redeployed to Fort Carson, Colorado after a successful 12-month combat deployment in Afghanistan.