Aston Rowant National Nature Reserve is located on the north-west escarpment of the Chiltern Hills, in the Chilterns Area of Outstanding Natural Beauty. It has an area of 159.1 hectares (393 acres), and most of it is a 128.5 hectares (318 acres) biological Site of Special Scientific Interest. It is listed as a Grade 1 site in A Nature Conservation Review. The reserve is in several sections, mostly in the parish of Lewknor in Oxfordshire, with smaller sections in the parish of Stokenchurch in Buckinghamshire.