Boulby Quarries is a 40.3 hectare geological Site of Special Scientific Interest in Redcar and Cleveland, North Yorkshire, England notified in 1989. It is located close to the coast and the village of Boulby.
Hartlepool Submerged Forest is a 19.7 hectare geological Site of Special Scientific Interest in County Durham, England notified in 1988. The site is located to the south of Hartlepool Docks.
Briarcroft Pasture is a 1.76 hectare biological Site of Special Scientific Interest in County Durham, England notified in 2004.
Cowpen Marsh is a 116.8 hectare biological Site of Special Scientific Interest in County Durham, England notified in 1966. SSSIs are designated by Natural England, formally English Nature, which uses the 1974–1996 county system. This means there is no grouping of SSSIs by Stockton-on-Tees unitary authority, or County Durham which is the relevant ceremonial county. As such Cowpen Marsh is one of 18 SSSIs in the Cleveland area of search.
Hart Bog is a 1.79 hectare biological Site of Special Scientific Interest in County Durham, England notified in 1968.
Seal Sands is a 294.37 hectare biological Site of Special Scientific Interest in County Durham, England, notified in 1966.
Lovell Hill Pools is a 9.2 hectare biological Site of Special Scientific Interest (SSSI) in North Yorkshire, England notified in 1999.
Seaton Dunes and Common is a 312.1 hectare biological Site of Special Scientific Interest in Hartlepool, County Durham, England notified in 1966. Part of it is a Local Nature Reserve.
Redcar Rocks is a 31.1 hectare biological and geological Site of Special Scientific Interest in North Yorkshire, England notified in 1984.
South Gare & Coatham Sands SSSI is a 381.2 hectare biological Site of Special Scientific Interest in North Yorkshire, England notified in 1971.
Tees and Hartlepool Foreshore and Wetlands SSSI is a 255.62-hectare (631.7-acre) biological Site of Special Scientific Interest in County Durham, England notified in 1997.
