The 108th Cavalry Regiment was constituted in the National Guard on 1 June 1921, allotted to the states of Georgia and Louisiana, and assigned to the 22nd Cavalry Division. It was organized from new and existing units. The 1st Squadron was organized on 6 March 1922 at Atlanta, Georgia, the 2nd Squadron was organized on 21 June 1922 at Jennings, Louisiana. The regimental headquarters was organized on 10 November 1923 and federally recognized at New Orleans, Louisiana. The regiment was relieved from the 22nd Cavalry Division on 19 February 1927 and assigned to the 23rd Cavalry Division. The regiment was reorganized on 15 March 1929 as a three-squadron regiment, with a new 3rd Squadron organized at New Orleans. The Headquarters was withdrawn from the state of Louisiana on 29 June 1936, allotted to the state of Georgia, and organized at Hinesville, Georgia. The regiment, less the Georgia elements, was called up to perform relief and guard duties associated with the flooding of the Mississippi River from 26 April to 19 June 1927. It conducted summer training most years at Fort Oglethorpe, Georgia, from 1921-1939, and at Camp McClellan, Alabama, in 1924, 1926–28, and 1933. The designated mobilization training station was Fort Oglethorpe. The 108th Cavalry Regiment was relieved from the 23rd Cavalry Division on 1 October 1940 and disbanded. Regimental elements used to form the 101st and 105th Separate Battalions, Coast Artillery (Antiaircraft).