In April 1967, General Westmoreland, who had arrived in June 1964 as Commander of MACV, organized a division-sized blocking force along the border between North and South Vietnam. The deployment of a division-sized U.S. Army force would allow the 3rd Marine Division to move north, to provide greater support for the 1st Marine Division in the northern portion of the I Corps Tactical Zone. Designated as Task Force Oregon, it included the 196th Infantry Brigade; the 3rd Brigade, 25th Infantry Division at Chu Lai; and the 1st Brigade, 10lst Airborne Division. On 25 September 1967 the new Americal Division (technically, the 23rd Infantry Division) was activated to control the blocking force, replacing the provisional task force HQ. With the elapse of five months, all the three same brigades remained in the new division, but the brigade at Chu Lai was now named the 3rd Brigade, 4th Infantry Division, after a responsibility swap that had occurred in August.