Strangford Lough or Strangford Loch 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. It is a conservation area and its abundant wildlife is recognised internationally for its importance. Strangford Lough was designated as Northern Ireland's first Marine Conservation Zones (MCZs) under the introduction of the Marine Act (Northern Ireland) 2013.