List of Sites of Special Scientific Interest in Hertfordshire

Hertfordshire is a county in eastern England. It is bordered by Bedfordshire to the north, Cambridgeshire to the north-east, Essex to the east, Buckinghamshire to the west and Greater London to the south. The county town is Hertford. As of 2018, the county has a population of 1,184,400 in an area of 634 sqmi.

As of July 2019, there are 43 sites designated within this Area of Search, 36 of which have been designated for their biological interest and 7 for their geological interest. In England the body responsible for designating SSSIs is Natural England, which chooses a site "because of its flora, fauna, or geological or physiographical features".

Interest

 * B = a site of biological interest
 * G = a site of geological interest

Other classifications

 * CAONB = Chilterns Area of Outstanding Natural Beauty
 * GCR = Geological Conservation Review
 * EWT = Essex Wildlife Trust
 * HMWT = Herts and Middlesex Wildlife Trust
 * LNR = Local nature reserve
 * NCR = A Nature Conservation Review
 * NNR = National nature reserve
 * NT = National Trust
 * Ramsar = Ramsar site
 * RHPG = Register of Historic Parks and Gardens of Special Historic Interest in England
 * RSPB = Royal Society for the Protection of Birds
 * SM = Scheduled monument
 * SPA = Special Protection Area
 * WT = Woodland Trust