There are 16 Sites of Special Scientific Interest (SSSIs) in the Blackdown Hills ranging from the Black Down and Sampford Commons to Reed Farm pit at just less than . This British conservation designation is administered in England by Natural England for areas with significant ecological characteristics deemed worthy of protection from inappropriate development or from other damage, and (since 2000) from neglect, under the Countryside and Rights of Way Act 2000. In total they cover , or just under 2% of the AONB. Of these SSSIs, 79% were deemed by Natural England's predecessor body, English Nature to be being positively managed.