[3] An area of 400 hectares (990 acres) in seven different patches has been designated a biological Site of Special Scientific Interest (SSSI), which is about half the size of an average English parish.

[5] The forest is mainly between the villages of Silverstone, Syresham, Abthorpe, Wicken, Potterspury and to the high Buckinghamshire boundary.

Remnants exist all around the villages and over the county boundary into Buckinghamshire and Milton Keynes; such outliers include Whistley Wood, west of Syresham.

Parts of the wood are protected as an SSSI, especially a number of separate copses which represent the remnants of the old semi-Royal Forest in the Honour of Grafton.

It is notable for bluebells in mid-Spring in many parts of the forest together with other ancient woodland indicator species such as Yellow rattle and the Lesser celandine.