The 6th Air Defense Artillery Regiment is an air defense artillery regiment in the United States Army, first formed in 1898 as the 6th Regiment of Artillery..
Constituted 8 March 1898 in the Regular Army as the "6th Regiment of Artillery". Organized 23 March 1898 at Fort McHenry, Maryland.
- The Regiment was broken up 13 February 1901 and its elements reorganized and redesignated as separate numbered companies and batteries of the Artillery Corps.
- Reconstituted 1 July 1924 in the Regular Army as the 6th Coast Artillery and partially organized with headquarters at Fort Winfield Scott, California. The regiment was organized by redesignating the 71st, 60th, 61st, 62nd, 63rd, 64th, 65th, 66th, 67th, 68th, & 69th Cos of the Coast Artillery Corps (CAC). Batteries A, B, C, E, F, H, I, and K carried the lineage and designations of the corresponding batteries in the old 6th Artillery. The regiment garrisoned portions of the Harbor Defenses of San Francisco. Headquarters and headquarters battery (HHB) and Batteries A, E, and K were the only components initially activated. HHB and Batteries A and E at Fort Winfield Scott, Battery K at Fort Baker.
- Battery K inactivated 30 September 1930.
- HHB 1st, and 2nd activated 1 July 1939 at Fort Winfield Scott, California; HHB 4th Battalion activated 15 January 1941 at Fort Funston, California.
- HHB 1st Battalion moved to Fort Barry 10 April 1942 until 16 November 1942, then to Fort Winfield Scott until 15 September 1945.
- HHB 2nd Battalion moved to Fort Baker 11 July 1939 until 31 August 1942. Moved to Fort Cronkhite 1 September 1942 until 15 September 1945.
- HHB 3rd Battalion activated at Fort Winfield Scott 2 June 1941 until 6 December 1941 when moved to Fort Miley until 15 September 1945.
- HHB 4th Battalion activated at Fort Funston 15 January 1941, moved to Fort Baker 19 January 1941, to Fort Barry 20 June 1941, to Fort Miley 27 January 1944.
- Batteries B and C activated at Fort Winfield Scott 1 July 1939. Battery C moved to Fort Miley 12 January 1942 until inactivated 10 September 1942. Battery D activated at Fort Barry 15 January 1941. Battery E posted at Fort Winfield Scott to 11 July 1939, moved to Fort Barry 15 January 1941, to Fort Cronkhite 6 June 1941 until 15 September 1945. Battery F activated at Fort Baker 1 August 40 and remained there until 10 June 1946.
- Battery G activated at Fort Cronkhite, moved to Fort Barry 10 April 1942 and redesignated Battery A, 6th Coast Artillery (HD) Battalion 18 October 1944. Battery H activated at Fort Baker 2 June 1941, moved to Fort Barry 4 October 1941 until redesignated Battery A, 172nd CA (HD) Battalion 18 October 1944. Battery I activated at Fort Baker 2 June 1941, moved to Fort Barry 22 June 1941 until redesignated Battery B, 172nd CA (HD) Battalion 18 October 1944.
- Battery K reactivated at Fort Baker 1 January 1931, moved to Fort Barry 12 March 1941 until inactivated 18 October 1944. Battery L activated at Fort Baker 15 January 1941, moved to Fort Barry 1 August 1941, moved to Camp Barkeley, Texas where inactivated 8 May 1944. Battery M activated at Fort Baker 15 January 1941, moved to Fort Barry 4 June 1941, to Fort Baker 6 October 1941, to Fort Barry 10 April 1942, to Fort Baker 4 November 1942, to Camp Barkeley, Texas where inactivated 8 May 1944. Battery N (Searchlight) activated at Fort Winfield Scott 15 January 1941 until 10 June 1946. Battery O activated at Ft. Miley 12 January 1942 and inactivated 10 September 1942.
- Regiment broken up 18 October 1944 and its elements reorganized and redesignated as follows: Headquarters and Headquarters Battery disbanded, 1st–4th Battalions reorganized and redesignated as the 6th, 172nd, 173rd, and 174th Coast Artillery Battalions, respectively.
- After 18 October 1944, the above units underwent changes as follows: Headquarters and Headquarters Battery, 6th Coast Artillery, reconstituted 28 June 1950 in the Regular Army concurrently consolidated with Headquarters and Headquarters Battery, 6th Antiaircraft Artillery Group, and consolidated unit designated as Headquarters Battery, 6th Artillery Group. Activated 1 February 1952 at Fort Bliss, Texas.
- Redesignated 20 March 1958 as Headquarters and Headquarters Battery, 6th Artillery Group. Inactivated 1 September 1971 at Fort Bliss, Texas.
- 6th Coast Artillery Battalion disbanded 15 September 1945 in California. Reconstituted 28 June 1950 in the Regular Army and redesignated as the 6th Antiaircraft Artillery Battalion. Redesignated 4 October 1950 as the 6th Antiaircraft Artillery Automatic Weapons Battalion, assigned to the 6th Infantry Division, and activated at Fort Ord, California. Inactivated 3 April 1956 to Fort Ord, California, and relieved from assignment to the 6th Infantry Division.
- The 172d Coast Artillery Battalion disbanded 15 September 1945 in California. Reconstituted 28 June 1950 in the Regular Army; concurrently consolidated with the 25th Antiaircraft Artillery Automatic Weapons Battalion (active), and consolidated unit designated as the 25th Antiaircraft Artillery Automatic Weapons Battalion, an element of the 25th Infantry Division. Inactivated 10 November 1951 in Korea and relieved from assignment to the 25th Infantry Division. Redesignated 19 November 1952 as the 25th Antiaircraft Artillery Gun Battalion. Activated 1 February 1953 in Germany. Redesignated 1 October 1953 as the 25th Antiaircraft Artillery Battalion. Redesignated 5 December 1957 as the 25th Antiaircraft Artillery Missile Battalion. Inactivated 1 September 1958 in Germany.
- The 173d Coast Artillery Battalion disbanded 15 September 1945 at Fort Miley, California. Reconstituted 28 June 1950 in the Regular Army and redesignated as the 45th Antiaircraft Artillery Battalion. Redesignated 9 March 1951 as the 45th Antiaircraft Artillery Gun Battalion. Activated 19 March 1951 at Fort Bliss, Texas. Redesignated 1 October 1953 as the 45th Antiaircraft Artillery Missile Battalion. Inactivated 1 September 1958 in Germany.
- The 174th Artillery Battalion disbanded 15 September 1945 in California. Reconstituted 28 June 1950 in the Regular Army and redesignated as the 53d Antiaircraft Artillery Battalion. Redesignated 21 April 1952 as the 53d Antiaircraft Artillery Gun Battalion. Activated 5 May 1952 in Japan. Inactivated 24 June 1955 in Japan. Redesignated 6 October 1955 as the 53d Antiaircraft Artillery Battalion. Activated 15 November 1955 at Fort Bliss, Texas. Inactivated 25 March 1957 at Fort Bliss, Texas.
- The 6th Antiaircraft Artillery Automatic Weapons Battalion; 25th and 45th Antiaircraft Artillery Missile Battalions; 53d Antiaircraft Artillery Battalion; and 6th Armored Field Artillery Battalion ( organized 1907) consolidated, reorganized and redesignated 1 September 1963 as the 6th Artillery, a parent regiment under the Combat Arms Regimental System.
- The 6th Artillery (less former 6th Armored Field Artillery Battalion) consolidated 1 September 1971 with Headquarters and Headquarters Battery, 6th Artillery Group, and consolidated unit reorganized and redesignated as the 11th Air Defense Artillery, a parent regiment under the Combat Arms Regimental Syste
