[5]: 130–5 In January 1970 John Paul Vann at the request of Ambassador Ellsworth Bunker produced his own evaluations of IV Corps' commanders which differed markedly from the official judgments of MACV.

[4]: 407 During 1971 the Division focused on destruction of People's Army of Vietnam (PAVN) and VC Base Area 400 in the That Son (Seven Mountains) region.

[7]: 15 During the Battle of An Lộc, on 15 May 1972 a task force of the 15th Regiment which was redeployed from the Mekong Delta to reinforce ARVN forces and the 9th Armored Cavalry Squadron, 21st Division moved north, east of Route 13 bypassing the People's Army of Vietnam (PAVN) 209th Regiment, 7th Division roadblock at Tau O (11°30′50″N 106°36′50″E / 11.514°N 106.614°E / 11.514; 106.614) to establish a fire support base at Tan Khai (11°33′00″N 106°36′58″E / 11.55°N 106.616°E / 11.55; 106.616) 10 km south of An Lộc.

With the 207th leading, supported by artillery, the PAVN attacked from Base Area 704 towards Hồng Ngự in an attempt to cut the South Vietnamese supply convoys up the Mekong River into Cambodia.

While US forces had disengaged from Vietnam on 28 January 1973 in accordance with the terms of the Paris Peace Accords, US military operations in Cambodia and Laos would continue until 15 August 1973 and the USAF was heavily engaged in support of the Khmer National Armed Forces campaign to clear the banks of the Mekong from the Vietnam border to Phnom Penh.

One B-52 strike on 23 April 1973 north of the border between the Mekong and the Hồng Ngự stream caught a large portion of the attacking force with survivors reported seeing impressed civilians carrying the bodies or more than 100 PAVN from the area.

Although casualties were heavy, Republic of Vietnam Air Force and Navy support helped enable the ARVN troops to clear the east bank of the Mekong from Hồng Ngự to the Cambodian frontier.