Site of Special Scientific Interest

A Site of Special Scientific Interest (SSSI) (Area of Special Scientific Interest or ASSI in Northern Ireland) is a conservation designation denoting a protected area in the United Kingdom. SSSIs are the basic building block of site-based nature conservation legislation and most other legal nature/geological conservation designations in Great Britain are based upon them, including national nature reserves, Ramsar sites, Special Protection Areas, and Special Areas of Conservation. The acronym "SSSI" is often pronounced "triple-S I".

SSSI selection and conservation

Sites notified for their biological interest are known as Biological SSSIs, and those notified for geological or physiographic interest are Geological SSSIs. SSSIs may be divided into management units, with some SSSI areas including units that are noted for both biological and geological interest.

Biological SSSIs

Biological SSSIs may be selected for various reasons, governed by published SSSI Selection Guidelines.