The 43rd Infantry Regiment was formed in June of 1917, at Fort Douglas, Utah. In April of 1921, it became a Philippine Scout unit and joined the Philippine Division, on October 22. In 1922, the unit was deactivated.
The 1st Battalion was reactivated on April 1, 1941, formed from troops transferred from the 45th Infantry Division (PS), and the 329 troops of the 1st Battalion served at Pettit Barracks and Camp John Hay. The 1st Battalion surrendered to the Japanese on April 9, 1942.
The unit was reorganized following the war, but disbanded a year later.
See also:
History of the 43rd Infantry Regiment