This is a list of the Sites of Special Scientific Interest (SSSIs) in County Durham, England. It excludes SSSIs situated in that area south of the River Tyne that is now part of the metropolitan county of Tyne and Wear as well as the area north of the River Tees which, prior to 1996, formed part of the county of Cleveland. As of July 2010, County Durham has 88 sites that have been designated as SSSIs, of which 67 have been designated for their biological interest, 16 for their geological interest, and 5 for both. Five of these sites are shared with an adjacent county: