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. It was designated a Local Nature Reserve in 2007. The River Chess runs through the estate which has formal parkland, meadows and mature woodland. Protected species include coralroot bittercress. Chorleywood Dell is a key neutral grassland site in the Biodiversity Action Plan for Hertfordshire. The gardens surround the 200-year-old manor house and summer house.