They say it happened just before 2:00 p.m. Monday. The accident was at the intersection of Route 75 (Green Valley Road) and Ed McClain Road, south of Adventure Park, U.S.A.
Police say the tractor trailer had lost control around a curve and landed on top of the pick-up truck.
A Maryland State Police helicopter was called to the scene to fly the driver of the tractor trailer, which was carrying fruit, to shock trauma. Police say the passenger in the tractor trailer was taken by ambulance to Fredrick Memorial Hospital.
The two people who died were inside the pick-up truck. A third passenger inside the truck was flown to shock trauma.
A witness was by the scene and told WHAG she heard the accident as it occurred.
"We heard the brakes of the truck," says Kathy Fox. "And then I heard a horn. It just kept blowing. It was probably two-three minutes solid before that horn went out."
Police are waiting to release the two victims names while family and friends are being contacted.
Expect heavy traffic along Route 75 for several hours while police investigate the crash.