Fleet Pond is a 48.3-hectare (119-acre) biological Site of Special Scientific Interest in Fleet in Hampshire. It is also a Local Nature Reserve.
Beacon Hill, Warnford is a 46.4-hectare (115-acre) biological Site of Special Scientific Interest west of Warnford in Hampshire. It is a Nature Conservation Review site, and an area of 40.1 hectares is a national nature reserve. There is a round barrow cemetery dating to the Late Neolithic or Bronze Age on the hill, and this is a scheduled monument.
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
Totternhoe Knolls is a 13.1-hectare (32-acre) Site of Special Scientific Interest (SSSI) in Totternhoe in Bedfordshire. It is also a local nature reserve, and part of the Chilterns Area of Outstanding Natural Beauty. The site is owned by Central Bedfordshire Council and leased to the National Trust. Most of the site is maintained jointly by the National Trust and the Wildlife Trust for Bedfordshire, Cambridgeshire and Northamptonshire (WTBCN), and is part of the WTBCN Totternhoe nature reserve, which also includes Totternhoe Chalk Quarry and Totternhoe Stone Pit. The SSSI also includes Totternhoe Castle, the earthworks of a Norman motte-and-bailey castle which is a Scheduled monument.
Turners Hill SSSI is a 0.2-hectare (0.49-acre) geological Site of Special Scientific Interest in Turners Hill in West Sussex. It is a Geological Conservation Review site.
Lye Valley is a 2.3-hectare (5.7-acre) biological Site of Special Scientific Interest in Headington, a suburb of Oxford in Oxfordshire. It is part of the 4.5-hectare (11-acre) Lye Valley Local Nature Reserve, which is owned and managed by Oxford City Council.
Old Park Wood is a 16.7-hectare (41-acre) Site of Special Scientific Interest in Harefield in the London Borough of Hillingdon. The south-east part is an 8-hectare (20-acre) nature reserve owned and managed by the Hertfordshire and Middlesex Wildlife Trust.
Mid Colne Valley is a 132 hectare biological Site of Special Scientific Interest in Harefield in the London Borough of Hillingdon and Denham in South Buckinghamshire. Its main importance lies in its extensive diversity of birdlife in lakes in former gravel pits.
Pilch Fields is an 11.1-hectare (27-acre) biological Site of Special Scientific Interest (SSSI) west of Great Horwood in Buckinghamshire. It is managed by the Berkshire, Buckinghamshire and Oxfordshire Wildlife Trust.
Froghall Brickworks is a 0.26-hectare (0.64-acre) geological Site of Special Scientific Interest east of Chalfont St Giles in Buckinghamshire.
Debden Water SSSI is a 20.9-hectare (52-acre) biological Site of Special Scientific Interest which comprises two stretches of Debden Water, a small tributary of the River Cam, and surrounding land. The site is on the eastern outskirts of Newport in Essex, where the stream joins the Cam.
Ashdown Park is a 9.3-hectare (23-acre) biological Site of Special Scientific Interest (SSSI) south of Ashbury in Oxfordshire. The SSSI is part of the park of Ashdown House.
River Mease SSSI is a 23.0 hectares biological Site of Special Scientific Interest. It is a stretch of the River Mease and its tributary Gilwiskaw Brook, running between Alrewas in Staffordshire and Packington in Leicestershire. It is also a Special Area of Conservation The river goes through private land, but it is crossed by roads and footpaths.
Stodmarsh SSSI is a 623.2-hectare (1,540-acre) biological Site of Special Scientific Interest near Stodmarsh, north-east of Canterbury in Kent. Parts of it are a Nature Conservation Review site, Grade I, a National Nature Reserve, a Ramsar internationally important wetland site, a Special Area of Conservation and a Special Protection Area under the European Union Directive on the Conservation of Wild Birds.
Buckland Warren is a 0.04-hectare (0.099-acre) biological Site of Special Scientific Interest (SSSI) east of Faringdon in Oxfordshire.
Little Wittenham SSSI is a 68.9-hectare (170-acre) biological Site of Special Scientific Interest north-east of Didcot in Oxfordshire. It is also a Special Area of Conservation.
Stonesfield Common, Bottoms and Banks is a 27.45-hectare (67.8-acre) biological Site of Special Scientific Interest (SSSI) south of Stonesfield in Oxfordshire.
Porton Down SSSI is a 1,559-hectare (3,850-acre) biological Site of Special Scientific Interest which spans the border between Hampshire and Wiltshire in England. It is adjacent to Porton Down science park near Porton, and much of it is Ministry of Defence property which is closed to the public. It is a Nature Conservation Review site, Grade I, a Special Area of Conservation and a Special Protection Area.
Lashford Lane Fen is a 7-hectare (17-acre) nature reserve north of Dry Sandford in Oxfordshire. It is managed by the Berkshire, Buckinghamshire and Oxfordshire Wildlife Trust. It is part of Cothill Fen, which is a Site of Special Scientific Interest and Special Area of Conservation.
