British Isles

The British Isles are an archipelago in the North Atlantic Ocean off the north-western coast of continental Europe, consisting of the islands of Great Britain, Ireland, the Isle of Man, the Inner and Outer Hebrides, the Northern Isles (Orkney and Shetland), and over six thousand smaller islands. They have a total area of 315,159 km (121,684 sq mi) and a combined population of almost 75 million, and include two sovereign states, the Republic of Ireland (which covers roughly five-sixths of Ireland) and the United Kingdom of Great Britain and Northern Ireland. The Channel Islands, off the north coast of France, are normally taken to be part of the British Isles, even though geographically they do not form part of the archipelago. Under the UK Interpretation Act 1978, the Channel Islands are clarified as forming part of the British Islands, not to be confused with the British Isles.

The oldest rocks are 2.7 billion years old and are found in Ireland, Wales and the north-west of Scotland. During the Silurian period, the north-western regions collided with the south-east, which had been part of a separate continental landmass. The topography of the islands is modest in scale by global standards. Ben Nevis, the highest mountain, rises to only 1,345 metres (4,413 ft), and Lough Neagh, which is notably larger than other lakes in the island group, covers 390 square kilometres (151 sq mi). The climate is temperate marine, with cool winters and warm summers. The North Atlantic drift brings significant moisture and raises temperatures 11 °C (20 °F) above the global average for the latitude. This led to a landscape that was long dominated by temperate rainforest, although human activity has since cleared the vast majority of forest cover. The region was re-inhabited after the last glacial period of Quaternary glaciation, by 12,000 BC, when Great Britain was still part of a peninsula of the European continent. Ireland was connected to Great Britain by the British-Irish Ice Sheet before 14,000 BC, and was not inhabited until after 8000 BC. Great Britain became an island by 7000 BC with the flooding of Doggerland.