The Regiment of Mounted Riflemen was authorized by an act of Congress in 1846 and brought into existence a new organization in the American Army: a regiment of riflemen, mounted for greater mobility than the infantry, and equipped with percussion rifles to provide greater range and accuracy than the muskets of the infantry or the dragoon's smooth bore carbines.
The Regiment participated in the Mexican War in 1847, distinguishing itself in six campaigns. Its participation there was climaxed by the bloody battle of Chapultepec. At the end of the Mexican War, The Regiment returned to Jefferson Barracks, Missouri, and marched to the Oregon Territory to accomplish the mission for which it had originally been organized.
After the outbreak of the Civil War in 1861, the Regiment of Mounted Riflemen found itself fighting Confederate Texans as well as Indians and in August of that year the Regiment was redesignated as the 3d United States Cavalry Regiment. Between October 1863 and March 1864, the Regiment fought in Tennessee, Mississippi, Alabama, and North Carolina as part of the advance guard of Sherman's Army. During the Spanish-American War, the 3d Cavalry Regiment participated in the attacks on San Juan and Kettle Hills. After the war, the Regiment was ordered to the Philippines to assist in quelling the Insurrection there. It fought 62 engagements between October 1899 and 1902. With the onset of World War I, the Regiment was transferred to Europe. Arriving in France in November 1917, the Regiment operated three remount depots for the duration of the war.
During the Second World War, the Regiment was redesignated the 3d Cavalry Group (Mechanized). The Group landed in France in August 1944 and became the spearhead of the XX Corps. The 3d Cavalry Group was the first unit of the 3rd U.S. Army to reach the Meuse and Moselle Rivers and to enter Germany. Upon returning to the United States, the 3d Cavalry Group was stationed at Ft. Meade, Maryland. On 5 November 1948, the 3d Cavalry Group (Mechanized) was redesignated as the 3d Armored Cavalry Regiment.
In 1961, the 3d Armored Cavalry Regiment again deployed to Germany in response to the Soviet threat during the Berlin Crisis. The Regiment remained in Germany until July 1968, when it redeployed to Fort Lewis, Washington.
In 1972, the Regiment relocated to Fort Bliss, Texas, where it trained in desert warfare and prepared for its REFORGER mission in the defense of Western Europe.
On 7 August 1990, the Regiment was alerted to move overseas in defense of Saudi Arabia. In September 1990, the Regiment arrived in country as part of the XVIII Airborne Corps, and moved into defensive positions south of the Kuwait border. On 22 January 1991, elements of I Troop led by the 63rd Colonel, Colonel Douglas Starr, engaged in the first ground combat of the XVIII Airborne Corps. On 22 February, F Troop led the Regiment across the berm into Iraq. In 100 hours, the Regiment moved over 300 kilometers, and left remnants of three Iraqi Republican Guard Divisions in its wake. In April of 1996, the Regiment completed a move to its new home at Fort Carson, Colorado.
In April 2003 the 3d ACR deployed in support of OIF I where it assumed responsibility for Al Anbar Province. The Regiment returned to Iraq in April 2005 with 3rd Squadron operating in the South Baghdad area and the rest of the Regiment in the region around Tal Afar.
Upon returning from Iraq, the 3d ACR once again moved to a new home station: Fort Hood, Texas. After an extensive train-up, the 3d ACR returned to Iraq in November, 2007 for a fifteen month deployment as part of the surge, serving in northern Iraq centered on Mosul as well as eastern Iraq in Diyala province. It returned to Fort Hood in February 2009.
After another extensive training period, the 3d ACR deployed back to Iraq in August of 2010 as the first brigade-size unit in support of Operation New Dawn. Our mission as a combat capable Advise and Assist unit focused on advising, training, and assisting Iraqi security forces and supporting five US State Department Provincial Reconstruction Teams to improve Iraq’s ability to defend their nation and improve civil capacity for the Iraqi people.
In 2011 the Regiment was again redesignated to meet the ever changing needs of the Nation. The Regiment of Mounted Riflemen changed their fighting platform from Abrams Tanks and Bradley Fighting Vehicles to the fast-moving, eight-wheeled Stryker Combat Vehicle. With this change, the name 3d Armored Cavalry Regiment became 3d Cavalry Regiment.
The 3d CR returned from Afghanistan in support of Operation Enduring Freedom that involved security missions and advising missions in eastern Afghanistan which ended on the last day of 2014. 3d CR participated in the transition to Operation Resolute Support in 2015 where the Brave Rifles primarily had a military and police advising role. These operations were conducted simultaneously with one squadron deployed to the Sinai Peninsula in Egypt for the ongoing Multi-National Force Observers mission and one troop deployed to perform security operations in Guantanamo Bay, Cuba.
Today, the 3d Cavalry Regiment remains at Fort Cavazos, formerly Fort Hood, and is postured to meet its assigned mission.