Strangford Lough (from Old Norse Strangr Fjörðr, meaning "strong sea-inlet") is a large sea loch or inlet in County Down, in the east of Northern Ireland. It is the largest inlet in the British Isles, covering 150 km2. The loch is almost totally enclosed by the Ards Peninsula and is linked to the Irish Sea by a long narrow channel or strait. The main body of the loch has at least seventy islands along with many islets (pladdies), bays, coves, headlands and mudflats. Strangford Lough was designated as Northern Ireland's first Marine Conservation Zone (MCZ) under the introduction of the Marine Act (Northern Ireland) 2013. It has also been designated a Special Area of Conservation under the EU Habitats Directive, and its abundant wildlife is recognised internationally for its importance.