1st Provisional Marine Brigade
After the Battle of Yongsan, General Walker let go of the 1st Provisional Marine Brigade from control of the 2nd Division. On September 5th, the 1st PMB started to leave Yongsan, and then they joined the 7th Marine Regiment and 1st Marine Regiment, 1st Marine Division since the 1st Marine Division was being reformed. MacArthur said that he could not fight in Inchon if there were no Marines, so he sent some of them to the Army's 65th Infantry Regiment and 17th Infantry Regiment.