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.
Chiddingfold Forest is a 542.5-hectare (1,341-acre) biological Site of Special Scientific Interest in Chiddingfold in Surrey and West Sussex. One part of it, Fir Tree Copse, is a nature reserve which is managed by the Surrey Wildlife Trust
Park Corner Heath is a 2.9-hectare (7.2-acre) biological Site of Special Scientific Interest about 1.2 miles (2 km) south of East Hoathly, adjacent to the A22 main road between Uckfield and Eastbourne in East Sussex. It is managed by Butterfly Conservation.
Kingston Escarpment and Iford Hill is a 63.4-hectare (157-acre) biological Site of Special Scientific Interest east of Brighton in East Sussex.
Amberley Wild Brooks or Amberley Wildbrooks is a 327.5-hectare (809-acre) biological Site of Special Scientific Interest west of Storrington in West Sussex. An area of 80 hectares is a nature reserve managed by the Sussex Wildlife Trust It is a Site of Special Scientific Interest and a Nature Conservation Review site. It is also part of the Arun Valley Ramsar site, Special Area of Conservation and Special Protection Area.
Castle Hill is a 114.6-hectare (283-acre) biological Site of Special Scientific Interest on the eastern outskirts of Brighton in East Sussex. It is a Special Area of Conservation and Nature Conservation Review site. The northern half is a national nature reserve
Turville Hill is a 22.4-hectare (55-acre) biological Site of Special Scientific Interest in Turville in Buckinghamshire. It is in the Chilterns Area of Outstanding Natural Beauty. Cobstone Windmill, also known as Turville Windmill, is located at the top.
Down Bank is a 5.9-hectare (15-acre) biological Site of Special Scientific Interest south-west of Canterbury in Kent.
Ranmore Common SSSI is a 224.3-hectare (554-acre) biological Site of Special Scientific Interest in Ranmore Common, north-west of Dorking in Surrey.
Scaynes Hill is a 0.04-hectare (0.099-acre) geological Site of Special Scientific Interest north-west of Newick in East Sussex. It is a Geological Conservation Review site.
Beeding Hill to Newtimber Hill is a 321-hectare (790-acre) biological and geological Downland Site of Special Scientific Interest (SSSI) north of Shoreham-by-Sea in West Sussex. It is a Nature Conservation Review site, Grade 2, and it includes Devil's Dyke Geological Conservation Review site.
Buchan Hill Ponds is a 19.5-hectare (48-acre) biological Site of Special Scientific Interest on the south-west outskirts of Crawley in West Sussex.
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.
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.
Ashford Hill Woods and Meadows is a 141.5-hectare (350-acre) biological Site of Special Scientific Interest near Ashford Hill in Hampshire. An area of 23.45 hectares is Ashford Hill NNR, which is a National Nature Reserve.
Stockbridge Down is a 69.8-hectare (172-acre) biological Site of Special Scientific Interest east of Stockbridge in Hampshire. It is a Nature Conservation Review site, Grade 2. It is owned by the National Trust and part of it is a Scheduled Monument, with an Iron Age hillfort and fourteen Bronze Age burial mounds.
