Constituted 27 February 1924 in the Regular Army as the 9th Coast Artillery (Harbor Defense) (HD) and organized as a Type B regimentBerhow, pp. 488-495 at Fort Banks in HD Boston on 1 July 1924 from the following companies of the Coast Artillery Corps: 172nd, 59th, 113th, 120th, 136th, 137th, 177th, 178th, and 9th Coast Artillery band; only regimental headquarters and headquarters battery (HHB) and Batteries A and C activated.Gaines, pp. 8-9
