The Ho Chi Minh Trail was a series of paths, roadways, and waterways used by North Vietnam to supply its armies in South Vietnam during the Vietnam War. All of the NVA's (North Vietnamese Army) supplies and over a million troops moved down the Ho Chi Minh trail from North to South Vietnam. The Trail was located mostly in Laos and Cambodia, countries that neighbor Vietnam. Due to political restrictions during the Cold War, the US could not invade Laos or Cambodia to shut the trail down, though we did frequently attack it with air strikes.
The trail is named after the leader of North Vietnam at that time, Ho Chi Minh.
There is isn't enough space here to tell the full story, so you'll need to do more research. The link below is a good place to start.