Relieved 1 December 1939 from assignment to the 3d Cavalry Division
Reorganized and redesignated 21 July 1942 as the 6th Cavalry, Mechanized
Regiment broken up 1 January 1944 and its elements reorganized and redesignated as follows:
Headquarters and Headquarters Troop as Headquarters and Headquarters Troop, 6th Cavalry Group, Mechanized
1st and 2d Squadrons as the 6th and 28th Cavalry Reconnaissance Squadrons, Mechanized, respectively
After 1 January 1944 the above units underwent changes as follows:
Headquarters and Headquarters Troop, 6th Cavalry Group, Mechanized, converted and redesignated 1 May 1946 as Headquarters and Headquarters Troop, 6th Constabulary Regiment
Redesignated 2 February 1948 as Headquarters, Headquarters and Service Troop, 6th Constabulary Regiment
6th and 28th Cavalry Reconnaissance Squadrons, Mechanized, converted and redesignated 1 May 1946 as the 6th and 28th Constabulary Squadrons, respectively
Above units converted and redesignated 20 December 1948 as the 6th Armored Cavalry (Headquarters, Headquarters and Service Troop, 6th Constabulary Regiment, as Headquarters and Headquarters Company, 6th Armored Cavalry; 6th and 28th Constabulary Squadrons as the 1st and 2d Battalions, 6th Armored Cavalry, respectively)
(Battalions and companies redesignated 24 June 1960 as squadrons and troops, respectively)
Regiment inactivated 24 October 1963 at Fort Knox, Kentucky
Activated 23 March 1967 at Fort George G. Meade, Maryland
Inactivated (less 1st Squadron) 31 March 1971 at Fort George G. Meade, Maryland
(1st Squadron inactivated 21 June 1973 at Fort Bliss, Texas)
Reorganized and redesignated 22 June 1973 as the 6th Cavalry, a parent regiment under the Combat Arms Regimental System
Withdrawn 16 July 1986 from the Combat Arms Regimental System and reorganized under the United States Army Regimental System
Company A, US 3rd Cavalry Redesignated 3 August 1861 as Company A, 6th Cavalry
(6th Cavalry assigned 15 August 1927 to the 3d Cavalry Division
Consolidated 14 October 1929 with Troop D, 6th Cavalry (organized in 1861) and consolidated unit designated as Troop A, 6th Cavalry
(6th Cavalry relieved 1 December 1939 from assignment to the 3d Cavalry Division)
Reorganized and redesignated 21 July 1942 as Troop A, 6th Cavalry, Mechanized
Reorganized and redesignated 1 January 1944 as Troop A, 6th Cavalry Reconnaissance Squadron, Mechanized
Converted and redesignated 1 May 1946 as Troop A, 6th Constabulary Squadron
Converted and redesignated 20 December 1948 as Company A, 6th Armored Cavalry (Former Troop D, 6th Cavalry, concurrently withdrawn from Company A, 6th Armored Cavalry - hereafter separate lineage)
Reorganized and redesignated 24 June 1960 as Troop A, 6th Armored Cavalry
Inactivated 24 October 1963 at Fort Knox, Kentucky
Activated 23 March 1967 at Fort George G. Meade, Maryland
Inactivated 21 June 1973 at Fort Bliss, Texas
Redesignated 22 June 1973 as Headquarters and Headquarters Troop, 1st Squadron, 6th Cavalry, assigned to the 1st Cavalry Division, and activated at Fort Hood, Texas (organic elements concurrently constituted and activated)
Relieved 21 February 1975 from assignment to the 1st Cavalry Division
Company B, 3rd Cavalry Redesignated 3 August 1861 as Company B, 6th Cavalry
Organized 16 August 1861 at Camp Scott, Pennsylvania
(Cavalry companies officially redesignated as troops in 1883)
(6th Cavalry assigned 15 August 1927 to the 3d Cavalry Division; relieved 1 December 1939 from assignment to the 3d Cavalry Division)
Reorganized and redesignated 21 July 1942 as Troop E, 6th Cavalry, Mechanized
Reorganized and redesignated 1 January 1944 as Troop F, 6th Cavalry Reconnaissance Squadron, Mechanized
Converted and redesignated 1 May 1946 as Troop E, 6th Constabulary Squadron
Converted and redesignated 20 December 1948 as Company B, 6th Armored Cavalry
Reorganized and redesignated 24 June 1960 as Troop B, 6th Armored Cavalry
Inactivated 24 October 1963 at Fort Knox, Kentucky
Activated 23 March 1967 at Fort George G. Meade, Maryland
Inactivated 21 June 1973 at Fort Bliss, Texas
Redesignated 1 July 1974 as Headquarters and Headquarters Troop, 2d Squadron, 6th Cavalry, and activated at Fort Knox, Kentucky (organic elements concurrently constituted and activated)
