# List of the largest Sites of Special Scientific Interest in England

This is a list of the largest Sites of Special Scientific Interest in England in decreasing order of size. A lower threshold of 100 hectares or one square kilometre has been used.

## Sites more than 10,000 hectares in size

| Site name | Area of Search | Reason for designation | Reason for designation | Area | Area | Grid reference | Year in which notified | Map |
| Site name | Area of Search | Biological interest | Geological interest | Hectares | Acres | Grid reference | Year in which notified | Map |
| The Wash | Norfolk / Lincolnshire | Y | | 63,135.0 | 156,010.0 | TF550400 | 1972 | |
| North York Moors | North Yorkshire / Cleveland | Y | | 44,087.7 | 108,943.1 | NZ680000 | 1998 | |
| Humber Estuary | East Riding of Yorkshire / Lincolnshire | Y | Y | 37,000.6 | 91,430.5 | TA216184 | 2004 | |
| Dark Peak | Derbyshire / Greater Manchester / South Yorkshire / West Yorkshire | Y | Y | 31,852.9 | 78,710.2 | SK110960 | 1951 | |
| Morecambe Bay | Cumbria / Lancashire | Y | | 30,287.5 | 74,842.0 | SD360700 | 1975 | |
| Upper Solway Flats and Marshes | Cumbria / ? | Y | Y | 29,950.5 | 74,009.3 | NY160610 | 1988 | |
| The New Forest | Hampshire / Wiltshire | Y | Y | 28,947.4 | 71,530.6 | SU298081 | 1959 | Map |
| South Pennine Moors | West Yorkshire / Great Manchester / Lancashire / North Yorkshire | Y | Y | 20,938.1 | 51,739.2 | SD920300 | 1994 | |
| Salisbury Plain | Wiltshire / Hampshire | Y | | 19,689.9 | 48,654.8 | SU070500 | 1975 | Map |
| Breckland Forest | Norfolk / Suffolk | Y | Y | 18,078.7 | 44,673.4 | TL819839 | 2000 | |
| Severn Estuary | Avon / Somerset + others | Y | Y | 15,950.0 | 39,413.3 | ST480830 | 1976 | |
| Upper Teesdale | County Durham | Y | Y | 14,035.6 | 34,682.7 | NY830320 | 1951 | |
| Moorhouse and Cross Fell | Cumbria / County Durham | Y | Y | 13,707.0 | 33,870.7 | NY715365 | 1990 | |
| Dee Estuary | Cheshire / Clwyd | Y | | 13,679.7 | 33,803.3 | SJ220800 | 1954 | |
| Breckland Farmland | Norfolk / Suffolk | Y | | 13,335.7 | 32,953.2 | TL762783 | 2000 | |
| North Dartmoor | Devon | Y | Y | 13,413.2 | 33,144.7 | SX580850 | 1952 | |
| North Exmoor | Devon / Somerset | Y | Y | 12,005.3 | 29,665.7 | SS800430 | 1954 | |

## Sites more than 4000 hectares in size

| Site name | Area of Search | Reason for designation | Reason for designation | Area | Area | Grid reference | Year in which notified | Map |
| Site name | Area of Search | Biological interest | Geological interest | Hectares | Acres | Grid reference | Year in which notified | Map |
| South Dartmoor | Devon | Y | Y | 9,668.2 | 23,890.6 | SX630690 | 1952 | |
| Hexhamshire Moors | County Durham / Northumberland | Y | | 9,433.9 | 23,311.7 | NY870530 | 1998 | Map |
| Kielderhead and Emblehope Moors | Northumberland | Y | | 8,254.4 | 20,397.1 | NT700000 | 1971 | |
| Eastern Peak District Moors | South Yorkshire / ? | Y | Y | 8,094.4 | 20,001.7 | SK270770 | 1955 | Map |
| Bollihope, Pikestone, Eggleston and Woodland Fells | County Durham | Y | | 7,949.2 | 19,642.9 | NZ005300 | 1996 | Map |
| North Norfolk Coast | Norfolk | Y | Y | 7,700.0 | 19,027.1 | TG020440 | 1954 | |
| Duddon Estuary | Cumbria | Y | Y | 6,806.3 | 16,818.7 | SD151753 | 1990 (amalgamated 5) | Map |
| Mersey Estuary | Cheshire / Merseyside | Y | | 6,702.1 | 16,561.2 | SJ440800 | 1951 | |
| The Swale | Kent | Y | Y | 6,568.4 | 16,230.9 | TR000670 | 1968 | |
| Blackwater Estuary | Essex | Y | Y | 5,738.0 | 14,178.9 | TL940070 | 1955 | |
| South Thames Estuary and Marshes | Kent | Y | | 5,449.1 | 13,465.0 | TQ770785 | 1951 | |
| Bodmin Moor, North | Cornwall | Y | | 4,957.0 | 12,249.0 | SX160810 | 1951 | |
| Kielder Mires | Cumbria / Northumberland | Y | | 4,818.0 | 11,905.5 | NY670800 | 1995 | |
| Bowes Moor | County Durham | Y | | 4,457.7 | 11,015.2 | NY923104 | 1989 | Map |
| Poole Harbour | Dorset | Y | | 4,049.0 | 10,005.3 | SZ000890 | 1964 | |

## Sites more than 2000 hectares in size

| Site name | Area of Search | Reason for designation | Reason for designation | Area | Area | Grid reference | Year in which notified | Map |
| Site name | Area of Search | Biological interest | Geological interest | Hectares | Acres | Grid reference | Year in which notified | Map |
| Chichester Harbour | Hampshire / West Sussex | Y | Y | 3,695.0 | 9,130.5 | SU760000 | 1970 | |
| Bridgwater Bay | Somerset | Y | | 3,574.1 | 8,831.8 | ST290480 | 1989 | |
| Dungeness | East Sussex / Kent | Y | Y | 3,241.7 | 8,010.4 | TR050180 | 1951 | |
| Ashdown Forest | East Sussex | Y | | 3,144.6 | 7,770.5 | TQ450300 | 1953 | |
| South Exmoor | Devon / Somerset | Y | | 3,132.7 | 7,741.1 | SS880340 | 1992 | |
| Long Mynd | Shropshire | Y | Y | 2,637.6 | 6,517.7 | SO420950 | 1953 | |
| Alde-Ore Estuary | Suffolk | Y | | 2,554.3 | 6,311.8 | TM394757 | 1952 | |
| The Quantocks | Somerset | Y | | 2,506.9 | 6,194.7 | ST140390 | 1970 | Map |
| Ouse Washes | Cambridgeshire / Norfolk | Y | | 2,403.0 | 5,937.9 | TL482867 | 1955 | |
| Exe Estuary | Devon | Y | Y | 2,186.6 | 5,403.2 | SX980845 | 1952 | |
| East Dartmoor | Devon | Y | Y | 2,088.1 | 5,159.8 | SX695815 | 1976 | |
| Langstone Harbour | Hampshire | Y | | 2,069.4 | 5,113.6 | SU700030 | 1958 | |

## Sites more than 1500 hectares in size

| Site name | Area of Search | Reason for designation | Reason for designation | Area | Area | Grid reference | Year in which notified | Map |
| Site name | Area of Search | Biological interest | Geological interest | Hectares | Acres | Grid reference | Year in which notified | Map |
| Thorne Crowle and Goole Moors | East Riding / South Yorkshire | Y | | 1,918.6 | 4,741.0 | SE730160 | 1970 | |
| Windsor Forest and Great Park | Berkshire / Surrey | Y | | 1,771.2 | 4,376.7 | SU970685 | 1973 | |
| Exmoor Coastal Heaths | Somerset | Y | | 1,758.3 | 4,344.9 | SS620480 | 1994 | Map |
| Wyre Forest | Shropshire / Hereford & Worcester | Y | | 1,753.7 | 4,333.5 | SS750760 | 1955 | |
| Epping Forest | Essex / Greater London | Y | | 1,728.0 | 4,270.0 | TL475035 | 1953 | |
| Porton Down | Wiltshire | Y | | 1,561.8 | 3,859.3 | SU240365 | 1977 | Map |
| Rutland Water | Leicestershire | Y | | 1,540.1 | 3,805.7 | SK928070 | 1981 | |

## Sites more than 1000 hectares in size

| Site name | Area of Search | Reason for designation | Reason for designation | Area | Area | Grid reference | Year in which notified | Map |
| Site name | Area of Search | Biological interest | Geological interest | Hectares | Acres | Grid reference | Year in which notified | Map |
| Upper Severn Estuary | Gloucestershire | Y | | 1,436.8 | 3,550.4 | SO720060 | 1954 | Map |
| Tamar - Tavy Estuary | Cornwall / Devon | Y | | 1,422.3 | 3,514.6 | SX474650 | 1991 | |
| Hatfield Moors | South Yorkshire | Y | | 1,400.7 | 3,461.2 | SE705060 | 1954 | |
| Avon Valley (Bickton to Christchurch) | Dorset / Hampshire | Y | | 1,383.7 | 3,419.2 | TU147123 | 1974 | |
| Braunton Burrows | Devon | Y | Y | 1,356.7 | 3,352.5 | SS430350 | 1952 | |
| Taw-Torridge Estuary | Devon | Y | | 1,336.5 | 3,302.6 | SS470310 | 1981 | |
| Nene Washes | Cambridgeshire | Y | | 1,310.0 | 3,237.1 | TL200977 | 1959 | |
| Portsmouth Harbour | Hampshire | Y | | 1,266.1 | 3,128.6 | SU620035 | 1974 | |
| East Devon Pebblebed Heaths | Devon | Y | | 1,111.9 | 2,747.6 | SY050880 | 1952 | |
| Catcott, Edington and Chilton Moors | Somerset | Y | | 1,083.0 | 2,676.2 | ST390420 | 1967 | Map |
| West Sedgemoor | Somerset | Y | | 1,016.0 | 2,510.6 | ST361258 | 1983 | Map |
| Haldon Forest | Devon | Y | | 1,013.2 | 2,503.7 | SX886838 | 1992 | Map |

## Sites more than 750 hectares in size

| Site name | Area of Search | Reason for designation | Reason for designation | Area | Area | Grid reference | Year in which notified | Map |
| Site name | Area of Search | Biological interest | Geological interest | Hectares | Acres | Grid reference | Year in which notified | Map |
| Chesil and the Fleet | Dorset | Y | Y | 990.4 | 2,447.3 | SY496885 | 1952 | |
| Fenn's, Whixall, Bettisfield, Wem and Cadney Mosses | Shropshire / Wales | Y | | 948.4 | 2,343.5 | SJ490365 | 1953 | |
| Tealham and Tadham Moors | Somerset | Y | | 917.6 | 2,267.4 | ST420450 | 1985 | Map |
| Savernake Forest | Wiltshire | Y | | 904.7 | 2,235.6 | SU215665 | 1971 | Map |
| King's Sedgemoor | Somerset | Y | | 822.0 | 2,031.2 | ST400330 | 1985 | |
| Grafham Water | Cambridgeshire | Y | | 811.9 | 2,006.2 | TL150680 | 1986 | |
| Durham Coast | Cleveland / Durham | Y | Y | 765.4 | 1,891.3 | NZ400500 | 1960 | |
| Rye Harbour | East Sussex | Y | Y | 761.1 | 1,880.7 | TQ935180 | 1953 | Map |
| Studland and Godlingston Heath | Dorset | Y | Y | 758.9 | 1,875.3 | SZ030845 | 1954 | |

## Sites more than 500 hectares in size

| Site name | Area of Search | Reason for designation | Reason for designation | Area | Area | Grid reference | Year in which notified | Map |
| Site name | Area of Search | Biological interest | Geological interest | Hectares | Acres | Grid reference | Year in which notified | Map |
| Blue Anchor to Lilstock Coast | Somerset | | Y | 742.8 | 1,835.5 | ST033435 | 1971 | |
| Abberton Reservoir | Essex | Y | | 716.3 | 1,770.0 | TL970180 | 1955 | |
| Lynher Estuary | Cornwall | Y | | 687.3 | 1,698.4 | SX375565 | 1951 | |
| North Moor | Somerset | Y | | 676.3 | 1,671.2 | ST325305 | 1986 | |
| Cotswold Commons And Beechwoods | Gloucestershire | Y | | 665.5 | 1,644.5 | SP900130 | 1954 | Map |
| Bentley Wood | Wiltshire / Hampshire | Y | | 665.0 | 1,643.3 | SU250295 | 1985 | Map |
| Barle Valley | Somerset | Y | | 622.9 | 1,539.2 | SS850349 | 1954 | |
| Pagham Harbour | West Sussex | Y | Y | 615.9 | 1,521.9 | SZ875970 | 1954 | |
| Upper Fal estuary and woodlands | Cornwall | Y | | 603.5 | 1,491.3 | SW850410 | 1968 | |
| Chew Valley Lake | Avon | Y | | 565.2 | 1,396.6 | ST570600 | 1971 | |
| Arne | Dorset | Y | Y | 563.4 | 1,392.2 | ST966880 | 1986 | |
| Westhay Moor | Somerset | Y | | 513.7 | 1,269.4 | ST455445 | 1971 | Map |
| Breydon Water | Norfolk | Y | | 506.5 | 1,251.6 | TG500075 | 1987 | Map |

## Sites more than 400 hectares in size

| Site name | Area of Search | Reason for designation | Reason for designation | Area | Area | Grid reference | Year in which notified | Map |
| Site name | Area of Search | Biological interest | Geological interest | Hectares | Acres | Grid reference | Year in which notified | Map |
| Wet Moor | Somerset | Y | | 491.0 | 1,213.3 | ST448244 | 1985 | Map |
| Curry and Hay Moors | Somerset | Y | | 472.8 | 1,168.3 | ST323273 | 1992 | Map |
| Dunster Park and Heathlands | Somerset | Y | | 466.6 | 1,153.0 | SS955441 | 2000 | Map |
| Cranborne Chase | Dorset / Wiltshire | Y | | 451.4 | 1,115.4 | ST970180 | 1975 | Map |
| Cheddar Complex | Somerset | Y | Y | 441.3 | 1,090.5 | ST465538 | 1952 | Map |
| Blithfield Reservoir | Staffordshire | Y | | 435.6 | 1,076.4 | SK057242 | 1968 | |
| Winterton to Horsey Dunes | Norfolk | Y | Y | 427.2 | 1,055.6 | ST490210 | 1954 | |
| Wytham Woods | Oxfordshire | Y | | 426.5 | 1,053.9 | SP462083 | 1950 | |

## Sites more than 300 hectares in size

| Site name | Area of Search | Reason for designation | Reason for designation | Area | Area | Grid reference | Year in which notified | Map |
| Site name | Area of Search | Biological interest | Geological interest | Hectares | Acres | Grid reference | Year in which notified | Map |
| Bratton Downs | Wiltshire | Y | Y | 395.8 | 978.0 | ST925522 | 1971 | Map |
| Shapwick Heath | Somerset | Y | | 394.0 | 973.6 | ST430403 | 1967 | Map |
| South Gare and Coatham Sands | Cleveland | Y | | 381.2 | 942.0 | NZ582263 | 1971 | |
| Isle of Portland | Dorset | Y | Y | 369.3 | 912.6 | SY690722 | 1952 | |
| Christchurch Harbour | Dorset | Y | Y | 353.2 | 872.8 | SZ175915 | 1964 | |
| Lundy | Devon | Y | | 345.0 | 852.5 | SS135460 | 1976 | |
| Axmouth to Lyme Regis Undercliffs | Devon / ? | Y | Y | 334.6 | 826.8 | SY300900 | 1952 | |
| Crook Peak to Shute Shelve Hill | Somerset | Y | Y | 332.2 | 820.9 | ST385555 | 1952 | Map |
| Fyfield Down | Wiltshire | Y | Y | 325.3 | 803.8 | SU136709 | 1951 | Map |
| Seaton Dunes And Common | Cleveland | Y | | 312.1 | 771.2 | NZ535285 | 1966 | |
| Pewsey Downs | Wiltshire | Y | | 305.3 | 754.4 | SU113636 | 1951 | Map |

## Sites more than 250 hectares in size

| Site name | Area of Search | Reason for designation | Reason for designation | Area | Area | Grid reference | Year in which notified | Map |
| Site name | Area of Search | Biological interest | Geological interest | Hectares | Acres | Grid reference | Year in which notified | Map |
| Church Wood, Blean | Kent | Y | | 297.1 | 734.2 | TR109603 | 1951 | |
| Seal Sands | Cleveland | Y | | 294.4 | 727.5 | NZ529260 | 1966 | |
| Lower Woods | Avon | Y | Y | 280.1 | 692.1 | ST743876 | 1966 | |
| Greenham and Crookham Commons | Berkshire | Y | | 278.6 | 688.4 | SU490645 & SU523643 | 1985 | |
| Lower Fal & Helford Intertidal | Cornwall | Y | | 277.7 | 686.2 | SW860334 | 1997 | |
| Tees and Hartlepool Foreshore and Wetlands | Cleveland | Y | | 255.6 | 631.6 | NZ516348 & NZ505224 | 1997 | |
| Skipwith Common | North Yorkshire | Y | | 274 | 677.1 | SE668362 | 1958 | |
| Slapton Ley | Devon | Y | Y | 254.7 | 629.4 | SX826440 | 2004 | |

## Sites more than 200 hectares in size

| Site name | Area of Search | Reason for designation | Reason for designation | Area | Area | Grid reference | Year in which notified | Map |
| Site name | Area of Search | Biological interest | Geological interest | Hectares | Acres | Grid reference | Year in which notified | Map |
| Longleat Woods | Somerset | Y | | 249.9 | 617.5 | ST795435 | 1972 | Map |
| Mottisfont Bats | Hampshire | Y | | 231.0 | 570.8 | SU314281 | 2003 | |
| Moorlinch | Somerset | Y | | 226.0 | 558.5 | ST390360 | 1985 | Map |
| West Moor | Somerset | Y | | 213.0 | 526.3 | ST420220 | 1985 | Map |
| Otmoor | Oxfordshire | Y | | 211.6 | 522.9 | SP575130 | 1952 | |
| Blagdon Lake | Avon | Y | | 212.7 | 525.6 | ST515597 | 1971 | |
| Ashton Court | Avon | Y | | 210.3 | 519.7 | ST553723 | 1998 | |

## Sites more than 150 hectares in size

| Site name | Area of Search | Reason for designation | Reason for designation | Area | Area | Grid reference | Year in which notified | Map |
| Site name | Area of Search | Biological interest | Geological interest | Hectares | Acres | Grid reference | Year in which notified | Map |
| Berrow Dunes | Somerset | Y | | 200.0 | 494.2 | ST293520 | 1952 | |
| Southlake Moor | Somerset | Y | | 196.1 | 484.6 | ST370300 | 1985 | Map |
| Brimsdown Hill | Wiltshire | Y | | 193.7 | 478.6 | SU831385 | 1951 | Map |
| Porlock Ridge and Saltmarsh | Somerset | Y | Y | 186.3 | 460.4 | SS880479 | 1990 | Map |
| Langmead and Weston Level | Somerset | Y | | 168.8 | 417.1 | ST353330 | 1991 | |
| Gordano Valley | Avon | Y | Y | 161.7 | 399.6 | ST435730 | 1971 | |
| East Blean Woods | Kent | Y | | 156.8 | 387.5 | TR189640 | 1981 | |
| St. Catherine's Valley | Avon | Y | | 156.1 | 385.7 | ST760725 | 1997 | |
| Avon Gorge | Avon | Y | Y | 155.4 | 384.0 | ST560743 | 1952 | |
| Black Down and Sampford Commons | Somerset | Y | | 155.2 | 383.5 | ST118161 | 1952 | |
| Brimble Pit and Cross Swallet Basins | Somerset | | Y | 154.3 | 381.3 | ST512505 | 1987 | |

## Sites more than 100 hectares in size

| Site name | Area of Search | Reason for designation | Reason for designation | Area | Area | Grid reference | Year in which notified | Map |
| Site name | Area of Search | Biological interest | Geological interest | Hectares | Acres | Grid reference | Year in which notified | Map |
| Attenborough Nature Reserve | Nottinghamshire | Y | | 226.6 | 559.9 | SK514338 | 1982 | Map |
| Asham Wood | Somerset | Y | | 141.6 | 349.9 | ST705460 | 1963 | |
| Burrington Combe | Avon / North Somerset | Y | Y | 139.1 | 343.7 | ST478583 | 1952 | |
| Wenlock Edge | Shropshire | Y | Y | 136.8 | 338.0 | SO606995 | 1954 | |
| Tickenham, Nailsea and Kenn Moors | Avon | Y | | 129.4 | 319.8 | ST440700 | 1995 | |
| Bowerchalke Downs | Wiltshire | Y | | 128.6 | 317.8 | SU004218 | 1971 | Map |
| Calstone And Cherhill Downs | Wiltshire | Y | | 128.6 | 317.8 | SU047692 | 1971 | Map |
| King's Wood and Urchin Wood | Avon | Y | | 128.1 | 316.5 | ST454645 | 1990 | |
| East Polden Grasslands | Somerset | Y | | 124.0 | 306.4 | ST474325 | 1999 | Map |
| Upper Fowey Valley | Cornwall | Y | | 124.0 | 306.4 | SX215730 | 1989 | |
| Potteric Carr | South Yorkshire | Y | | 119.6 | 295.5 | SE599003 | 1977 | |
| Cowpen Marsh | Cleveland | Y | | 116.8 | 288.6 | NZ500529 | 1966 | |
| River Kennet | Berkshire / Wiltshire | Y | | 112.7 | 278.5 | SU203692 | 1995 | Map |
| Cheddar Reservoir | Somerset | Y | | 105.4 | 260.4 | ST441537 | 1972 | Map |
| River Barle | Somerset | Y | | 104.2 | 257.5 | SS723423 | 1997 | Map |
| Dozmary Pool | Cornwall | Y | Y | 104.2 | 257.5 | SX195745 | 1986 | |
| Prior's Park & Adcombe Wood | Somerset | Y | | 103.6 | 256.0 | ST225170 | 1952 | Map |