From 1968 to 1970 Operation Igloo White, run out of Nakhon Phanom in Thailan, bombed it round-the-clock by B-52's.  
It was under the operational command of the 559th Transportation group, and it became more important after the naval interdiction efforts of Operation Market Time began to tell.  It was the target of Operations Steel Tiger and Barrell Roll, as well as the Popeye project, which aimed to reduce its effectiveness by extending the monsoon season through cloud-seeding.  From 1968 to 1970 Operation Igloo White, run out of Nakhon Phanom in Thailan, bombed it round-the-clock by B-52's.  Throughout its operation, both sides ignored theoretical Laotian neutrality, and it was instrumental in preparations for the Tet Offensive.  Known in Vietnamese as the Truong Son Strategic Supply Route, FTP name this corridor that funneled supplies from North Vietnam to the Viet Cong in the south.
It was under the operational command of the 559th Transportation group, and it became more important after the naval interdiction efforts of Operation Market Time began to tell.  
Ho Chi Minh Trail (Accept Truong Son Strategic Supply Route before it is mentioned)