- Constituted 14 August 1917 in the National Guard as Headquarters, 42d Division
- Organized 5 September 1917 at Camp Mills, New York
- Demobilized 9 May 1919 at Camp Dix, New Jersey
- Reconstituted 5 February 1943 in the Army of the United States as Headquarters, 42d Infantry Division
- Activated 14 July 1943 at Camp Gruber, Oklahoma
- Inactivated 29 June 1946 in Austria
- Reorganized and Federally recognized 31 March 1947 in the New York National Guard at New York
- Ordered into active Federal service 24 March 1970 at New York; released from active Federal service 30 March 1970 and reverted to state control
- Location changed 1 December 1989 to Troy; Headquarters Company concurrently organized from Headquarters and Headquarters Company, 205th Support Group (See ANNEX)
- Ordered into active Federal service 24 May 2004 at Troy; released from active Federal service 19 December 2005 and reverted to state control
- Consolidated 1 September 2006 with Detachment 1, 42d Armored Division Artillery (organized and Federally recognized 25 January 2002 at Troy), and consolidated unit designated as Headquarters, 42d Infantry Division
- Reorganized 1 September 2011 in the New York and New Jersey Army National Guard as Headquarters and Headquarters Battalion, 42d Infantry Division
- ANNEX
- Organized 21 June 1916 in the New York National Guard at Troy as Headquarters Company, 2d Infantry Regiment
- Mustered into Federal service 1 July 1916 at Troy; mustered out of Federal service 23 October 1916 at Troy
- Mustered into Federal service 31 March 1917 at Troy; drafted into Federal service 5 August 1917
- Reorganized and redesignated 1 October 1917 as Headquarters Company, 105th Infantry, an element of the 27th Division
- Demobilized 1 April 1919 at Camp Upton, New York
- Reorganized and Federally recognized 15 January 1920 in the New York National Guard at Troy as Headquarters Company, 2d Infantry
- Redesignated 1 June 1921 as Headquarters Company, 105th Infantry
- (105th Infantry assigned 17 November 1921 to the 27th Division [later redesignated as the 27th Infantry Division])
- Inducted into Federal service 15 October 1940 at Troy
- Inactivated 31 December 1945 at Fort Lawton, Washington
- Reorganized and Federally recognized 4 March 1947 at Troy
- Reorganized and redesignated 1 February 1955 as Headquarters and Headquarters Company, Combat Command A, 27th Armored Division
- Reorganized and redesignated 16 March 1959 as Headquarters and Headquarters Company, 1st Brigade, 27th Armored Division
- Converted and redesignated 1 February 1968 as Headquarters and Headquarters Company, 205th General Support Group, and relieved from assignment to the 27th Armored Division
- Reorganized and redesignated 1 December 1971 as Headquarters and Headquarters Company, 205th Support Group
HOME STATION: Troy (less detachments at Buffalo, Staten Island, and Lawrenceville, New Jersey)