Cornwall (; Cornish: Kernow; Cornish pronunciation: [ˈkɛrnɔʊ]; or [ˈkɛrnɔ]) is a ceremonial county in South West England. It is recognised by Cornish and Celtic political groups as one of the Celtic nations, and is 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 settlement is Falmouth, and the county town is the city of Truro.

The county is rural, with an area of 1,375 square miles (3,562 km²) and population of 568,210. After Falmouth (23,061), the largest settlements are Penzance, Newquay, St Austell, and Truro. For local government purposes most of Cornwall is a unitary authority area, with the Isles of Scilly having 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. Its coastline is characterised by steep cliffs and, to the south, several rias, including those at the mouths of the rivers Fal and Fowey.