43^rd Infantry Regiment

The 43rd Infantry Regiment (Philippine Scouts) had a fragmentary wartime record rather than the full campaign history of a standard three-battalion regiment. Its 1st Battalion was activated on Luzon on April 1, 1941, and later attached to the Bataan Defense Force and Philippine Division. The regiment's Scout personnel were connected administratively with the Philippine Division system, but the division itself seldom fought as a unified formation after the Japanese invasion began. Its regular regiments, detachments, artillery, engineers, and service troops were repeatedly shifted among USAFFE, Bataan Defense Force, II Philippine Corps, and later I Philippine Corps during the defense of Bataan.

The 1st Battalion's Bataan service came in this fragmented command environment. The Philippine Division moved from Fort William McKinley through the Clark Field and Subic Bay areas, then into Bataan. By late January 1942 the division held Sub-Sector D under II Philippine Corps, with its infantry regiments detached for front-line employment. As starvation, disease, air attack, artillery fire, and Japanese infantry pressure weakened the garrison, the final enemy offensive struck in late March and early April. On April 6, 1942, the 1st Battalion, 43rd Infantry, was destroyed on Bataan during the same crisis that wrecked the division's remaining infantry combat power.

The regiment's other known wartime elements were Companies C and E, which had been at Zamboanga on Mindanao. After Japanese landings there, these companies served in the defensive arrangements around the Sayre Highway and Mangima Canyon. They were lost near Dalirig on May 9, 1942, shortly before organized American and Filipino resistance on Mindanao collapsed. The regiment's World War II combat record therefore consists of separated Philippine Scout detachments overwhelmed in the final defensive battles of Bataan and Mindanao.