9,000 psychiatric patients are buried at Horton Cemetery.
The land is the former home of a cluster of hospitals in Epsom that served the south and east London.
The patients were buried there between 1899 and 1955.
In 1983 the NHS transferred the Cemetery to a property speculator who eventually dismantled all the tombstones and grave markers.
A team of 50 researchers is now campaigning for the cemetery to be put back into community use.
Residents are being invited to an event in the field next to the cemetery next Tuesday the 10th from 1pm.