Syon Park is the garden of Syon House, the London home of the Duke of Northumberland in Isleworth in the London Borough of Hounslow. It was landscaped by Capability Brown in the 18th century, and it is Grade I listed by English Heritage under the Historic Buildings and Ancient Monuments Act 1953 for its special historic interest. The 56.6-hectare (140-acre) main gardens are a Site of Borough Importance for Nature Conservation, Grade I, and the flood meadows next to the River Thames are a biological Site of Special Scientific Interest (SSSI) and a Site of Metropolitan Importance for Nature Conservation.
Cock Marsh is an area of marsh land and steep chalk slope covering more than 150-acre (61-hectare) north of Maidenhead in Berkshire. It includes a 45-acre (18-hectare) biological Site of Special Scientific Interest. It is also the location of a Round barrow cemetery and common land where livestock have grazed for hundreds of years. Cock Marsh is owned and managed by the National Trust.
Colony Bog and Bagshot Heath is a 1,130.5-hectare (2,794-acre) biological Site of Special Scientific Interest between Camberley and Woking in Surrey, England. Part of it is a Nature Conservation Review site, Grade I. It is part of the Thames Basin Heaths Special Protection Area and the Thursley, Ash, Pirbright and Chobham Special Area of Conservation. It includes Brentmoor Heath, a Local Nature Reserve which is managed by the Surrey Wildlife Trust
Ingrebourne Marshes are a 74.8 hectare biological Site of Special Scientific Interest in Hornchurch in the London Borough of Havering. Ingrebourne Valley Local Nature Reserve includes a small part of the SSSI west of the River Ingrebourne. The site is managed by the Essex Wildlife Trust
Glyme Valley is a 28.9-hectare (71-acre) biological Site of Special Scientific Interest east of Chipping Norton in Oxfordshire. An area of 3 hectares is a nature reserve managed by the Berkshire, Buckinghamshire and Oxfordshire Wildlife Trust
Sizewell Marshes form a 260-acre biological Site of Special Scientific Interest adjacent to Sizewell in Suffolk. It is in the Suffolk Coast and Heaths Area of Outstanding Natural Beauty, and is part of a 356-acre (144-ha) nature reserve managed by the Suffolk Wildlife Trust as Sizewell Belts.
Old Rectory Meadows is a 7.9-hectare (20-acre) Site of Special Scientific Interest in Denham in Buckinghamshire.
Long Herdon Meadow is a 4.5-hectare (11-acre) biological Site of Special Scientific Interest south of Marsh Gibbon in Buckinghamshire. It is part of Upper Ray Meadows nature reserve, which is managed by the Berkshire, Buckinghamshire and Oxfordshire Wildlife Trust.
Tingewick Meadows is an 11.1-hectare (27-acre) biological Site of Special Scientific Interest south of Tingewick in Buckinghamshire.
Rodbed Wood is a 2.2-hectare (5.4-acre) biological Site of Special Scientific Interest in Medmenham in Buckinghamshire. It is in the Chilterns Area of Outstanding Natural Beauty.
Arncott Bridge Meadows is an 8.7-hectare (21-acre) biological Site of Special Scientific Interest in Arncott in Oxfordshire.
Snailwell Meadows is a 14.8-hectare (37-acre) biological Site of Special Scientific Interest in Snailwell in Cambridgeshire.
Wadenhoe Marsh and Achurch Meadow is a 47.5-hectare (117-acre) biological Site of Special Scientific Interest south of Wadenhoe in Northamptonshire.
Empingham Marshy Meadows is a 14 hectare biological Site of Special Scientific Interest north of Empingham in Rutland.
South Thames Estuary and Marshes is a 5,289-hectare (13,070-acre) biological Site of Special Scientific Interest which stretches between Gravesend and the mouth of the River Medway in Kent. Part of it is a Nature Conservation Review site, Grade I, and part is a Royal Society for the Protection of Birds nature reserve. It is part of the Thames Estuary and Marshes Ramsar internationally important wetland site and Special Protection Area under the European Union Directive on the Conservation of Wild Birds.
Charleshill SSSI is a 10.1-hectare (25-acre) biological Site of Special Scientific Interest west of Elstead in Surrey. It is part of Thundry Meadows nature reserve, which is owned and managed by the Surrey Wildlife Trust
Iffley Meadows is a 36.1-hectare (89-acre) biological Site of Special Scientific Interest in Oxford in Oxfordshire. It is owned by Oxford City Council and managed by the Berkshire, Buckinghamshire and Oxfordshire Wildlife Trust
Bramshill is a 673.3-hectare (1,664-acre) biological Site of Special Scientific Interest near Bramshill, northeast of Basingstoke in Hampshire. It is part of Thames Basin Heaths Special Protection Area for the conservation of wild birds.
Eelmoor Marsh is a 66.3-hectare (164-acre) biological Site of Special Scientific Interest between Fleet and Farnborough in Hampshire. It is part of Thames Basin Heaths Special Protection Area for the conservation of wild birds.
Foxlease and Ancells Meadows is a 68.8-hectare (170-acre) biological Site of Special Scientific Interest on the western outskirts of Farnborough in Hampshire.The site is in seven areas, two of which are nature reserves managed by the Hampshire and Isle of Wight Wildlife Trust, Ancells Farm and Whitehouse Meadow.
