- Organized 5 August 1895 in the California National Guard at Salinas as Troop C, Cavalry.
- Redesignated 1 May 1911 as Troop C, 1st Squadron of Cavalry.
- Mustered into Federal service 26 June 1916 at Sacramento; mustered out of Federal service 17 November 1916 at Los Angeles.
- Reorganized and redesignated 3 October 1917 as Company B, 145th Machine Gun Battalion, an element of the 40th Division.
- Drafted into Federal service 5 November 1917.
- Demobilized 20 May 1919 at the Presidio of San Francisco, California.
- Reorganized and Federally recognized 18 June 1924 in the California National Guard at Salinas as the 40th Tank Company and assigned to the 40th Division.
- Reorganized and redesignated 1 September 1940 as Company C, 194th Tank Battalion, and relieved from assignment to the 40th Division.
- Inducted into Federal service 10 February 1941 at Salinas.
- Surrendered 9 April 1942 to the Japanese 14th Army in the Philippine Islands.
- Inactivated 2 April 1946 in the Philippine Islands.
- Expanded and redesignated 21 June 1946 as the 199th Tank Battalion.
- Reorganized and Federally recognized 27 May 1947 with Headquarters at Salinas.
- Reorganized and redesignated 1 February 1949 as the 149th Heavy Tank Battalion and assigned to the 49th Infantry Division.
- Reorganized and redesignated 1 September 1950 as the 149th Tank Battalion.
- Consolidated 1 May 1959 with the 170 Antiaircraft Artillery Battalion (see ANNEX) and consolidated unit reorganized and redesignated as the 149th Armor, a parent regiment under the Combat Arms Regimental System, to consist of the 1st Medium Tank Battalion and the 2nd Reconnaissance Squadron, elements of the 49th Infantry Division.
- Reorganized 1 March 1963 to consist of the 1st and 3rd Battalions, elements of the 49th Infantry Division, and the 4th Medium Tank Battalion.
- Reorganized 1 April 1964 to consist of the 1st and 3rd Battalions, elements of the 49th Infantry Division, and the 4th Battalion.
- Reorganized 29 January 1968 to consist of the 1st Battalion.
- Reorganized 13 January 1974 to consist of the 1st Battalion, an element of the 40th Infantry Division.
- Withdrawn 19 January 1988 from the Combat Arms Regimental System and reorganized under the United States Army Regimental System.
- 1st Battalion ordered into active Federal service 1 May 1992 at home stations; released 9 May 1992 from active Federal service and reverted to state control.
ANNEX
- Constituted 13 July 1946 in the California National Guard as the 118th Cavalry Reconnaissance Squadron, Mechanized.
- Organized and Federally recognized 8 June 1949 as the 118th Mechanized Cavalry Reconnaissance Squadron, with Headquarters at Red Bluff.
- Reorganized and redesignated 15 September 1959 as the 2nd Battalion, 111th Armored Cavalry.
- Converted and redesignated 1 June 1954 as the 170th Antiaircraft Artillery Battalion.
CAMPAIGN PARTICIPATION CREDIT
- World War I Streamer without inscription
- World War II Philippine Islands
- Company C (Santa Cruz), 1st Battalion, additionally entitled to: World War II - AP, Aleutian Islands
DECORATIONS
- Presidential Unit Citation (Army), Streamer embroidered: DEFENSE OF THE PHILIPPINES
- Presidential Unit Citation (Army), Streamer embroidered: LUZON 1941-1942
- Presidential Unit Citation (Army), Streamer embroidered: BATAAN PENINSULA
- Philippine Presidential Unit Citation, Streamer embroidered: 7 DECEMBER 1941 TO 10 MAY 1942