Designation can be used to protect areas of value and scientific interest and to ensure that such areas are properly managed. This includes areas of particular value for the conservation of species, habitats, historic and cultural assets and landscapes of great value or beauty.
Designation is driven by a goal to conserve and enhance such areas and is underpinned by UK and international legislation. Development within or near designated areas is subject to additional controls.
SSSIs were first established in 1949 by the Nature Conservancy so that the conservation of important sites of natural habitat, wildlife and geological heritage could be taken into account during the planning process. Today, Natural England has responsibility for identifying and protecting SSSIs in England under the provisions of the Wildlife and Countryside Act.
- Ancient woodlands.
- Species-rich grasslands.
- Coastal marshes and mudflats.
- Unique geological formations.
 Special Areas of Conservation (SAC)
 Special Protection Areas (SPA)
In Scotland, a National Scenic Area (NSA) is a part of the countryside with high scenic value of national importance and interest that has statutory protection to conserve and enhance the natural beauty of its landscape.
National Scenic Areas (NSAs) include:
- Mountain ranges.
- Diverse landscapes.
 National Nature Reserves (NNR)
Marine protected areas include Special Areas of Conservation (SACs) for habitats of European importance, Special Protection Areas (SPAs) for birds, Marine Conservation Zones (MCZs) and Marine Nature Reserves designated to conserve marine flora and fauna and features of special interest.
 Local Nature Reserves (LNR)
LNRs are areas of special local wildlife or geological interest.
Other local sites where restrictions might apply include registered common land and registered town or village greens. In addition, conservation areas, tree preservation orders and listed buildings require additional consent for development.
- Ancient woodland.
- Areas of Outstanding Natural Beauty.
- Archaeology and construction.
- Archaeological officer.
- Blue belt.
- Civic Amenities Act.
- Common area.
- Conservation areas.
- Conservation officer.
- Designated land.
- Ecological network.
- European sites.
- Heritage Action Zone.
- Historic England.
- Listed buildings.
- Local green space.
- Local interest list.
- Local Nature Reserve.
- Making Local Nature Recovery Strategies deliver.
- National nature reserves.
- National parks.
- National Scenic Area NSA.
- Natural England.
- Natural environment white paper.
- Nature improvement area.
- Ramsar sites.
- Scheduled monuments.
- Site of biological importance.
- Site of Nature Conservation Interest (SNCI).
- Sites of Special Scientific Interest.
- Special areas of conservation.
- Special protection areas.
- Statutory authorities.
- Statutory permissions.
- The history of conservation areas.
- Tree preservation orders.
- Types of land.
- Village greens.
- World heritage site.
 External references
- Natural England Designations Strategy 2012.
- Natural England: Designated sites.
- Commons Act 2006.
- Guidance on competent authority coordination under the Habitats Regulations
- Joint Nature Conservation Committee.