Chanctonbury Hill is an 82.7-hectare (204-acre) biological Site of Special Scientific Interest west of Steyning in West Sussex. Part of it is Chanctonbury Ring, an early Iron Age hillfort which contains two Romano-Celtic temples and which is a Scheduled Monument.
Kingley Vale is a 204.4-hectare (505-acre) biological Site of Special Scientific Interest north of Chichester in West Sussex. It is also a Special Area of Conservation and a Nature Conservation Review site, Grade I. An area of 147.9 hectares is a national nature reserve.
Ditchling Common is a 66.5-hectare (164-acre) biological Site of Special Scientific Interest south-west of Wivelsfield in East Sussex. It is a country park. which is owned and managed by East Sussex County Council. In many respects, it is a biologically important site of the Low Weald supporting a rich array of biodiversity not found anywhere else in the area.
Willingdon Down is a 67.5-hectare (167-acre) biological Site of Special Scientific Interest west of Willingdon, a suburb of Eastbourne in East Sussex. Part of it is a Neolithic causewayed enclosure which is a Scheduled Monument
Wilmington Downs is a 209.8-hectare (518-acre) biological Site of Special Scientific Interest north-west of Eastbourne in East Sussex. The site includes a Scheduled Monument, the Long Man of Wilmington, a turf cut figure which may be of prehistoric origin.
St Dunstan's Farm Meadows is a 10.2-hectare (25-acre) biological Site of Special Scientific Interest south-east of Heathfield in East Sussex. It is in the High Weald Area of Outstanding Natural Beauty.
Amberley Mount to Sullington Hill is a 177.2-hectare (438-acre) biological Site of Special Scientific Interest south-west of Storrington in West Sussex.
Arun Banks is a 25.8-hectare (64-acre) biological Site of Special Scientific Interest north of Arundel in West Sussex.
Burton Park SSSI is a 57.7-hectare (143-acre) biological Site of Special Scientific Interest west of Pulborough in West Sussex. A larger area of 63 hectares, including Chingford Pond to the west, is designated a Local Nature Reserve called Burton and Chingford Ponds, which is managed by the Sussex Wildlife Trust and West Sussex County Council. The site is adjacent to Burton Park, a Grade I listed building.
Duncton to Bignor Escarpment is a 229-hectare (570-acre) biological Site of Special Scientific Interest west of Pulborough in West Sussex. It is a Special Area of Conservation and Bignor Hill is a Nature Conservation Review site, Grade I.
Fairmile Bottom is a 70.2-hectare (173-acre) biological Site of Special Scientific Interest north-west of Arundel in West Sussex. An area of 61.3 hectares is also a Local Nature Reserve.
Harting Downs is a 336.3-hectare (831-acre) biological Site of Special Scientific Interest west of Midhurst in West Sussex. It is a Nature Conservation Review site, Grade I and an area of 206.6 hectares is a Local Nature Reserve which is owned and managed by the National Trust.
Lavington Common is a 31.2-hectare (77-acre) biological Site of Special Scientific Interest south-west of Petworth in West Sussex. It is a National Trust property.
Levin Down is a 25.6-hectare (63-acre) biological Site of Special Scientific Interest south of Midhurst in West Sussex. It is managed by the Sussex Wildlife Trust.
West Harting Down SSSI is a 13.9-hectare (34-acre) biological Site of Special Scientific Interest west of South Harting in West Sussex. It is part of the 317.9-hectare (786-acre) West Harting Down, which is managed by Forestry England.
Sullington Warren is a 24.7-hectare (61-acre) biological Site of Special Scientific Interest in Storrington in West Sussex. The site includes several tumuli which are Scheduled Monuments.
Heyshott Down is a 42.6-hectare (105-acre) biological Site of Special Scientific Interest south of Midhurst in West Sussex. It is a Nature Conservation Review site, Grade 2.
Coulters Dean is a 2.2-hectare (5.4-acre) biological Site of Special Scientific Interest south-east of Buriton in Hampshire. It is part of the 4-hectare (9.9-acre) Coulters Dean nature reserve, which is managed by the Hampshire and Isle of Wight Wildlife Trust.
Martin and Tidpit Downs is a 367.5-hectare (908-acre) biological Site of Special Scientific Interest north-west of Fordingbridge in Hampshire. Martin Down is a 341-hectare (840-acre) national nature reserve and an area of 115 hectares is a Nature Conservation Review site, Grade I. Bokerley Dyke, a prehistoric linear earthwork and scheduled monument, runs through the site.
