The 191st Infantry Brigade was constituted on 24 June 1921 in the Organized Reserves as Headquarters and Headquarters Company, 191st Infantry Brigade, and assigned to the 96th Division. It was organized in December 1921 at Portland, Oregon, and redesignated on 23 March 1925 as Headquarters and Headquarters Company, 191st Brigade, then redesignated on 24 August 1936 as Headquarters and Headquarters Company, 191st Infantry Brigade. It was converted and redesignated on 6 April 1942 as the 96th Reconnaissance Troop, 96th Division. The Troop was ordered into active military service on 15 August 1942 and reorganized at Camp Adair, Oregon, as the 96th Cavalry Reconnaissance Troop, an element of the 96th Infantry Division. It was reorganized and redesignated on 16 August 1943 as the 96th Reconnaissance Troop, Mechanized, and then again reorganized and redesignated on 20 November 1945 as the 96th Mechanized Cavalry Reconnaissance Troop. Following World War II service with the 96th Infantry Division in the Pacific, it was inactivated on 3 February 1946 at Camp Anza, California.