Three Rivers is a local government district in south-west Hertfordshire, England. Its council is based in Rickmansworth.
Totternhoe Knolls is a 13.1 hectare 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.
Norton Common is a 25.7-hectare park and Local Nature Reserve in the centre of Letchworth Garden City, Hertfordshire. It is owned and managed by North Hertfordshire District Council, and the declaring authority is Hertfordshire County Council.
Aston Rowant National Nature Reserve is located on the north-west escarpment of the Chiltern Hills, in the Chilterns Area of Outstanding Natural Beauty. It has an area of 159.1 hectares, and most of it is a 128.5 hectare biological Site of Special Scientific Interest. It is listed as a Grade 1 site in A Nature Conservation Review. The reserve is in several sections, mostly in the parish of Lewknor in Oxfordshire, with smaller sections in the parish of Stokenchurch in Buckinghamshire.
Rowley Green Common is a six hectare Local Nature Reserve and a Site of Importance Metropolitan for Nature Conservation in Arkley, north London. It is owned by the London Borough of Barnet and according to the Natural England details page it is jointly managed by the Hertfordshire and Middlesex Wildlife Trust and the London Wildlife Trust, but as of August 2015 it is not on the list of reserves of either Trust. It is also registered common land.
Colney Heath Local Nature Reserve is a 22.5 hectare Local Nature Reserve in Colney Heath in Hertfordshire. It is owned by St Albans City Council and managed by Colney Heath Parish Council. The site was acquired in the 1950s and 1960s, and it is a Hertfordshire Heritage Site.
Frogmore Meadows is a 4.6 hectare biological Site of Special Scientific Interest in Hertfordshire and Buckinghamshire, north of the village of Chenies. It consists of two meadows in the Chilterns Area of Outstanding Natural Beauty, next to the River Chess, one of which is a Hertfordshire and Middlesex Wildlife Trust nature reserve. The planning authorities are Three Rivers District Council, Dacorum Borough Council and Chiltern District Council.
Northaw Great Wood is a 223.6 hectare biological Site of Special Scientific Interest (SSSI) near Cuffley in Hertfordshire, England. It covers Northaw Great Wood Country Park, which is managed by Welwyn Hatfield Borough Council, Well Wood, Justice Hill and Grimes Bottom. Part of the site is managed by Hertfordshire County Council as a schools' park. The country park is also a local nature reserve.
Chorleywood House Estate is a 64.3 hectare Local Nature Reserve in Chorleywood in Hertfordshire. It is owned and managed by Three Rivers District Council, and the declaring authority is Hertfordshire County Council.
Mardley Heath is a 41.1 hectare Local Nature Reserve in Welwyn in Hertfordshire. It is owned by Welwyn Hatfield Borough Council and managed by the council together with the Friends of Mardley Heath.
Oughtonhead Common is a 17.4 hectare Local Nature Reserve in the Westmill district of Hitchin, Hertfordshire. It is owned and managed by North Hertfordshire District Council.
Stanborough Reedmarsh is a 3.3 hectare Local Nature Reserve in Welwyn Garden City in Hertfordshire. It is owned by Welwyn Hatfield Borough Council and managed by the Herts and Middlesex Wildlife Trust.
Shrubhill Common is a 9.8 hectare Local Nature Reserve in Hemel Hempstead in Hertfordshire. It is owned and managed by Dacorum Borough Council. The site is common land, and it is part of the Chilterns Area of Outstanding Natural Beauty.
Purwell Meadows is an 8.6 hectare nature reserve in Hitchin, Hertfordshire, England. It was declared a Local Nature Reserve in 1994. It is owned and managed by North Hertfordshire District Council.
Weston Hills is a 17 hectare Local Nature Reserve in Baldock in North Hertfordshire. It is owned by Hertfordshire County Council and North Hertfordshire District Council (NHDC) and managed by NHDC.
Marshalls Heath is a 4 hectare Local Nature Reserve in Wheathampstead in Hertfordshire. It is owned by Wheathampstead Parish Council and managed by the council together with the Friends of Marshalls Heath. It was purchased from The Queen's College, Oxford, in 1966.
Wheathampstead Local Nature Reserve is a 5.9 hectare Local Nature Reserve (LNR) in Wheathampstead in Hertfordshire. It was declared an LNR by St Albans City Council in 2002, and is leased by Wheathampstead Parish Council from Hertfordshire County Council.
Prestwood Local Nature Reserve or Prestwood is a 2.1 hectares Local Nature Reserve in Prestwood in Buckinghamshire. It is in the Chilterns Area of Outstanding Natural Beauty. The site is owned by Wycombe District Council and leased to the Chiltern Society.
