Friends and family of those who died will be at a service later.
It follows two years of research into the area's wartime past by conservation organisations in Surrey.
A memorial made of two wing tips, carved by sculptor Roger Day, has been placed at the site. It includes fuselage aluminium from the crash.
Mark Richards, from the National Trust, said archaeologists had carried out surveys of unidentified military structures and researchers had delved into the national archives to find out more about how the B17G aircraft crashed.
He said the memorial was one of the abiding legacies of the Front Line Surrey Hills project.
"Its beauty and poignancy [is] striking in what is now known as the memorial glade," he said.
Researchers discovered the crew from 384th Bomb Group were on their 13th mission together and their target for 19 March 1945 was to be the oil facilities at Bohlen, Germany.
During the mission, the crew bombed secondary targets because they were hampered by cloud.
On their return, cloud led to further visibility problems and the aircraft crashed into Reigate Hill in a huge explosion.
The clearing at the crash site was created by the force as the aircraft crashed into the beech trees.
The Front Line Surrey Hills project, which included the Surrey Hills Area of Outstanding Natural Beauty, the National Trust, Gatton Trust and Surrey County Council, received Â£54,000 from the Heritage Lottery Fund for its programme of educational and research events.
A memorial is being unveiled for a World War Two American aircraft crew who died when their plane crashed 70 years ago on Reigate Hill.