Constituted 1917 and organized CD Boston 12-1-17 as 55th Arty, CAC, by redesignation of 152nd Co, CAC;, 96th Co, CAC; 11th Co,
MANG, CAC; 83rd Co, CAC; 4th Co, MANG; 9th Co,
RING; 3rd Co MANG; and 5th Co, MANG. In addition, many individual transfers were made from the 1st, 2nd, 6th, & 9th Cos, MANG, and 13th Co, RING. The 55th Arty departed New York for Europe 3–25–18. After additional training, the 55th Arty was assigned to the 31st Bde, CAC, in August 1918 and served in France until the Armistice. The 55th Arty departed Brest, arriving New York 1-22-19 and moved to
Camp Mills, NY, until 1–26–19, when it moved to CD Long Island Sound. 1st Bn was stationed at
Fort H.G. Wright, 2nd & 3rd Bns at
Fort Terry. There most of the regiment's NG and
National Army personnel were discharged. On 1-29-19 the 55th Arty CAC was transferred with 31st Bde to
Fort Winfield Scott, arriving 2-23-19 with 9 officers and 170 EM. The 31st Bde was then transferred to
Fort Lewis, WA, arriving 10–4–19, and its strength was gradually built up to near peacetime levels. In April 1921, the 55th Arty was assigned to Hawaii. The 31st Bde was broken up and personnel from the 57th Arty were reassigned to the 55th Arty and to the
59th Arty slated for the Philippines. This enabled the 55th to activate HHD&CTs of the 1st, 2nd, and 3rd Bns, as well as to moderately reinforce the firing batteries. In addition, Service Btry was activated. The 55th Arty arrived in Honolulu 5-12-21 and was posted to
Fort Kamehameha. The regiment was soon reorganized. The three battalions were restructured with three batteries each by reassigning personnel from three companies manning fixed seacoast armament. This resulted in the activation of Btrys G, H, & I and the relocation of 1st Bn to
Fort Shafter and 2nd Bn to
Fort Ruger. On 6–1–22, each component of the 55th Arty received an additional serially numbered company designation. These additional designations were dropped on 7–1–24, when the regiment was redesignated 55th CA (TD) (Tractor Drawn) Regt. Personnel shortages resulted in a 10-31-25 reorganization; the 3rd Bn was inactivated at Ft. Shafter, its personnel reassigned to 1st Bn, replacing personnel transferred to the 64th CA (AA) Regt. The reorganized 1st Bn, 55th CA, moved to Ft. Kamehameha and Service Btry combined with HHB. At this time Btry C, 55th CA, transferred to the 64th CA (AA) Regt as Btry I. A new Btry C was constituted and activated in the 55th CA. In the mid-1930s, 2nd Bn HHB moved to
Fort DeRussy although its firing batteries remained at
Fort Ruger. On 2–17–41, AA detachments were organized in Btrys E & F to man fixed
3-inch AA guns at Ft. Ruger and Sand Is. On 12–7–41, the 55th CA was posted around Oahu: Btrys A, B, & C on Oahu's southwest coast between Pearl Harbor and Kaena Point, Btrys D & E on the northeast coast, and Btry F on Sand Is. On 12–27–41, Btry D moved from Ft. Ruger to the Island of Kauai, where it established Camp Kauai. When filler personnel arrived from the mainland at the end of June 1942, two officers and 69 enlisted men from Battery C, 55th CA, with a pair of
155 mm GPF mobile seacoast guns was deployed to Canton Island in January 1942 where they later also manned four
4-inch navy guns. Battery D was reinforced to its authorized wartime strength. Detachments from Btry A formed Btry 80-X in December 1941; a second detachment helped form the 804th CA (HD) Btry (Sep). Btry F at Sand Is. was designated the 807th CA (HD) Btry (Sep), while a second detachment helped organize the 715th CA (HD) Btry (Sep) 10–21–42. During World War II, various changes were made in the makeup of the 55th CA. The 55th CA (155 mm Gun) Regt was reorganized and HHB reconstituted and activated; 1st, 2nd, and 3rd Bn HHBs were activated at Ft. Ruger 5–22–43. Btry G (SL) was activated at Ft. Kamehameha. The 1st Bn HHB and Btrys A, B, & C, and 2nd Bn HHB were stationed at Ft. Kamehameha, Btry D on Kauai, Btry E at Wilridge. A detachment from Btry F was at Sand Is. The 811th CA (HD) Btry (Sep) was activated 8–1–42, at Hilo, HI, with personnel from Btry B. In September 1943 Btry E manned Btry Willy's
155 mm guns on Wiliwilinui Ridge near Btry Wilridge, an
8-inch naval turret battery. Btry F was posted at Camp Punchbowl, a 155 mm position overlooking Honolulu. Both batteries were released from Hawaiian Seacoast Artillery Command 9-30-43 and moved to Ewa, Oahu, staging for deployment to the Gilbert Islands in the Central Pacific as components of army defense battalions providing garrison forces. Btry E went to Tarawa and Btry F to Apamama in 5-31-44 when the 55th CA Regt was inactivated. HHB 3rd Bn at Ft. Ruger was inactivated 5-31-44 and its personnel reassigned to HHB 179th CA (155 mm Gun) Bn, which shortly thereafter moved to Kahuku, in HD Kaneohe Bay and North Shore. Personnel of Btry E reassigned to Btry A and personnel of Btry F reassigned to Btry B, 179th CA Bn. Both Btrys A & B, 179th CA Bn, returned to Oahu soon thereafter. The 55th CA was disbanded 6–14–44. In the late 1950s and early 1960s, the regiment included: • Battalion; Station; Activated; Inactivated • 1/55
New York Defense Area Sept. 1958 26 July 1960 • 2/55
Hartford Defense Area Sept. 1958 24 December 1964 • 3/55
Detroit Defense Area Sept. 1958 23 December 1960 • 4/55
Thule Air Base (Greenland) 1 Sept. 1958 20 December 1965 ==Distinctive unit insignia==