The regimental headquarters was organized on 24 January 1924 and federally recognized at Sheridan, relocating on 11 April 1924 to Cheyenne.

The 115th Cavalry reorganized on 1 June 1929 as a three-squadron regiment, with a new 3rd Squadron organized at Casper, Wyoming.

The regiment was concurrently relieved from the 24th Cavalry Division, and on 30 December 1940 was assigned to the IX Corps.

It was inducted into active federal service on 24 February 1941 at Cheyenne and transferred on 10 March 1941 to Fort Lewis, Washington.

While the 115th Cavalry Group, with the 106th and 107th Cavalry Reconnaissance Squadrons attached, served overseas in France and Germany, the 115th and 126th Squadrons never went overseas; the 126th was inactivated on 15 August 1944 at Fort Jackson, South Carolina, and the 115th was inactivated on 6 March 1945 at Camp Polk, Louisiana.

[2] The 115th Cavalry Reconnaissance Squadron was redesignated as the 300th Armored Field Artillery Battalion and allotted to the Wyoming National Guard 29 July 1946.

A Gold color metal and enamel device 1+5⁄32 inches (2.9 cm) in height overall consisting of a shield blazoned: Gules, five fleurs-de-lis Or one, three, and one, on a chief embattled Azure fimbriated of the second a demi-sun issuant of the like.