It has been owned by the National Trust since 1968, when it was bought with the help of a donation from the Heinz company as part of Enterprise Neptune.
Dunwich Heath is a rare survival of coastal lowland heath; the Suffolk Sandlings used to form a lot of the Suffolk coast, but have mostly been developed for agriculture or built upon.
A variety of birds, animals and reptiles live on the heath; red deer, muntjacs, Dartford warblers, European stonechats, and European nightjars, as well as adders, slowworms, grass snakes and common lizards.
Dunwich Heath Cliff is designated a regionally important geological site.
The layers of large flint cobbles are known locally as the "Westleton Beds".