Cornwall ( ; Cornish: Kernow [ˈkɛrnɔʊ] or [ˈkɛrnɔ]) is a ceremonial county in South West England. It is also one of the Celtic nations and the homeland of the Cornish people. The county is bordered by the Atlantic Ocean to the north and west, Devon to the east, and the English Channel to the south. The largest urban area is the Redruth and Camborne conurbation.

The county is predominantly rural, with an area of 1,375 square miles (3,562 km²) and population of 568,210. After the Redruth-Camborne conurbation, the largest settlements are Falmouth, Penzance, Newquay, St Austell, and Truro. For local government purposes most of Cornwall is a unitary authority area, with the Isles of Scilly governed by a unique local authority. The Cornish nationalist movement disputes the constitutional status of Cornwall and seeks greater autonomy within the United Kingdom.

Cornwall is the westernmost part of the South West Peninsula, and the southernmost county within the United Kingdom. Its coastline is characterised by steep cliffs and, to the south, several rias, including those at the mouths of the rivers Fal and Fowey.