Cornwall is aunitary authority and ceremonial county of England, within the United Kingdom. Cornwall is a peninsula bordered to the north and west by the Celtic Sea, to the south by the English Channel, and to the east by the county of Devon, over the River Tamar. Cornwall has a population of 535,300 and covers an area of 3,563 km2 (1,376 sq mi). The administrative centre, and only city in Cornwall, is Truro.
Cornwall forms the westernmost part of the south-west peninsula of the island of Great Britain, and a large part of the Cornubian batholith is within Cornwall. This area was first inhabited in the Palaeolithic and Mesolithic periods. It continued to be occupied by Neolithic and then Bronze Age peoples, and later (in the Iron Age) by Brythons with distinctive cultural relations to neighbouring Wales and Brittany. There is little evidence that Roman rule was effective west of Exeter and few Roman remains have been found. Cornwall was the home of a division of theDumnonii tribe—whose tribal centre was in the modern county of Devon—known as the Cornovii, separated from the Brythons of Wales after the Battle of Deorham, often coming into conflict with the expanding English kingdom ofWessex before King Athelstan in AD 936 set the boundary between English andCornish at the Tamar. From the early Middle Ages, British language and culture was apparently shared by Brythons trading across both sides of the Channel, evidenced by the corresponding high medieval Breton kingdoms of Domnonee andCornouaille and the Celtic Christianity common to both territories.
