45^th Infantry Regiment

The 45th Infantry Regiment (Philippine Scouts) was stationed at Fort William McKinley and served as one of the Philippine Division's two Scout infantry regiments. In 1941 much of the division was dispersed, and the 1st Battalion, less one company, was at Limay on Bataan before the campaign. After the Japanese landing and air attacks opened the Philippines campaign, the division moved through Clark Field and Subic Bay into the Bataan defense, where the 45th formed part of the main reserve available to USAFFE and later the Bataan Defense Force.

The regiment's major early commitment came after Japanese forces broke into the 51st Division sector near Abucay. On January 16, 1942, the 45th and 31st Infantry counterattacked to restore the line. The attack suffered from confusion, difficult ground, and determined Japanese resistance; after five days of fighting, the force was defeated with heavy losses. The division then withdrew to the reserve battle line near Pilar and Bagac and on January 26 came under II Philippine Corps. During the following weeks its units helped contain patrols and limited attacks while Bataan's defenders fought the Battle of the Points and reduced the Toul Pocket.

The final Japanese offensive shattered the division sector. On April 6 the 45th and 31st counterattacked but were forced back toward the Mamala River after severe losses. Before dawn on April 7, the 2nd Battalion, reinforced by two tanks, attacked east along Trail 8 toward Trail Junction 6-8 while the 3rd Battalion held near Trail Junction 8-28. The lead elements entered a Japanese ambush, one tank was knocked out, and the attack could not break through. The 2nd Battalion withdrew to the Pantingan River by midmorning, and the 3rd Battalion fought out by evening. The failed attack ended the effort to reunite Sector D; the regiment then passed to I Corps control and surrendered on Bataan on April 9, 1942.