Thetford Heaths is a 270.6-hectare (669-acre) biological and geological Site of Special Scientific Interest in Suffolk. It is a Nature Conservation Review site, Grade I, and parts of it are a national nature reserve, and a Geological Conservation Review, It is part of the Breckland Special Area of Conservation, and Special Protection Area A large part of this dry heathland site is calcareous grassland, and some areas are grazed by sheep or rabbits. There are several nationally rare plants and an uncommon heathland bird, and many lichens and mosses.