Organized in February 1918 at Camp Upton, New York, as Company C, 1st Separate Battalion, Heavy Tank Service, 65th Engineers

Reorganized and redesignated 16 March 1918 as Company C, 1st Heavy Battalion, Tank Service

Reorganized and redesignated 16 April 1918 as Company C, 41st Heavy Battalion, Tank Corps

Reorganized and redesignated 11 June 1918 as Company C, 301st Battalion, Tank Corps Expanded, reorganized, and redesignated 22 June 1921 as Companies A, B, and C, 16th Tank Battalion (Companies A and B -- hereafter separate lineages)

Reorganized and redesignated 1 September 1929 as Company C, 1st Tank Regiment

Converted and redesignated 25 October 1932 as Company C, 66th Infantry (Light Tanks)

Converted and redesignated 15 July 1940 as Company C, 66th Armored Regiment, an element of the 2d Armored Division

Reorganized and redesignated 25 March 1946 as Company C, 66th Tank Battalion, and remained an element of the 2d Armored Division

Redesignated 5 January 1949 as Company C, 66th Medium Tank Battalion

Redesignated 1 April 1953 as Company C, 66th Tank Battalion

Inactivated 1 July 1957 and relieved from assignment to the 2d Armored Division

Reorganized and redesignated 10 June 1958 as Headquarters and Headquarters Company, 3d Medium Tank Battalion, 66th Armor (organic elements concurrently constituted)

Battalion activated 25 June 1958 at Fort Benning, Georgia

Inactivated 25 June 1959 at Fort Benning, Georgia

Headquarters and Headquarters Company redesignated 9 September 1959 as Company C, 66th Armor, and assigned to the 1st Infantry Brigade (remainder of 3d Medium Tank Battalion, 66th Armor, concurrently disbanded)

Activated 24 September 1959 at Fort Benning, Georgia

Inactivated 24 September 1962 at Fort Benning, Georgia, and relieved from assignment to the 1st Infantry Brigade

Redesignated 8 August 1963 as Headquarters and Headquarters Company, 3d Battalion, 66th Armor (organic elements concurrently constituted)

Activated 1 September 1980 and assigned to the 2nd Armored Division at Fort Hood, Texas. In the mid 1980’s, the Battalion was assigned to 2nd Armored Division (Forward) in Garlstadt, West Germany as a part of NATO Northern Army Group.

Inactivated 15 April 1992 at Garlstadt, West Germany .

Activated 16 December 1992 at Fort Hood Texas and on 16 January 1996, 3rdBattalion 66th Armor was relieved from assignment to 2nd Armored Division and assigned to the 4th Infantry Division.

Inactivated 16 December 2004 at Fort Hood, Texas.

Activated 17 March 2008 in Schweinfurt, Germany and assigned to 172nd Separate Infantry Brigade.

Unit history the way that the Center of Military History doesn't record