Group 559 Group 559 was a transportation and logistical unit of the People ' s Army of Vietnam that was subordinate to the Rear Services General Directorate . Group 559 was established on 19 May 1959 in order to move troops , weapons , and material ( by sea and land ) from the North Vietnam to South Vietnam and to build and maintain support facilities en route . The troop consisted with two transportation battalions . The purpose of this unit was to establish supply line s from North Vietnam to Vietcong paramilitary units in South Vietnam . This task was made more difficult by the presence of a demilitarized zone ( DMZ ) on the border separating the two countries , though the North Vietnamese did send some supplies across the DMZ , their major infrastructure went around it . Group 559 developed road lines through Laos and Cambodia that fed into various areas of northern and western South Vietnam . This system of roads became known as the Ho Chi Minh Trail , and was used under the supervision of Group 559 to infiltrate weapons , ammunition , and cadres into the South . The purpose of these activities was the support of Vietcong in their struggle to topple the southern regime of President Ngo Dinh Diem . In 1960 , Group 559 is upgraded to division - level , and established the 70th Regiment . In 1961 , the 71st Regiment was set up . By 1962 the group ' s force level was 6 , 000 troops organized into two regiments equipped with bicycles and a few trucks . Within one year the force level grew to 24 , 000 troops and six motorized transport battalions plus engineering , anti - aircraft , and security elements . After the commitment of U . S . and allied forces to the Vietnam War in 1965 , Group 559 moved a volume of supplies nearly equal to the total volume of the preceding five years . Increasing North Vietnamese involvement , including the introduction of large ground units , in the southern war and U . S . interdiction of PAVN ' s logistical system at sea sharply increased the group ' s overland route . On April 3 , 1965 , Group 559 acquired the corps - level status of a Military Region reporting directly to the Military Affairs Party Committee and the General Staff , with three subordinate commands for the supply corridors through Laos . Preparations for large - scale main force offensives , both during and after the U . S . withdrawal sharply increased logistical requirements . In July 1973 the group , redesignated the Truong Son Command , converted sectoral and way station forces into divisions or regiments and established five additional regiments . By late 1974 , forces under its command included Anti - Aircraft Division 377 , Infantry Division 968 , the 5 regional commands ( division - level ) : 470th , 471st , 472nd , 473rd and 571st . plus fourteen regiments and various repair facilities and hospitals with total personnel of 100 , 495 . During Vietnam War , Group 559 transported more than one million tons cargo into the front , inside over 500 , 000 tons delivered into theater B ( ) . In 1975 when the war ended , Group 559 was reorganized into 12th Corps ( ) to rebuild Ho Chi Minh Trail into roads for economics and national defense . Group 579 and Group 959 were created somewhat later , with similar but different missions . Group 579 was charged with infiltrating supplies into South Vietnam by sea , complementing the land based operations of Group 559 . It was created in May 1959 . ( Conboy " et al . " , p . 8 ) Group 959 was created to move supplies to Pathet Lao forces in Laos .