The total area of the United Kingdom is approximately 245,000 square kilometres (94,600 sq mi) comprising of the island of Great Britain, the northeastern one-sixth of the island of Ireland (Northern Ireland) and smaller islands. It lies between the North Atlantic Ocean and the North Sea, coming within 35 kilometres (22 mi) of the northwest coast of France, from which it is separated by the English Channel. Great Britain lies between latitudes 49° and 59° N (the Shetland Islands reach to nearly 61° N), and longitudes 8° W to 2° E. The Royal Greenwich Observatory, in London, is the defining point of the Prime Meridian. When measured directly north-south, Great Britain is a little over 1,100 kilometres (700 mi) in length and is a fraction under 500 kilometres (300 mi) at its widest, but the greatest distance between two points is 1,350 kilometres (840 mi) between Land's End in Cornwall (near Penzance) and John o' Groats in Caithness (near Thurso). Northern Ireland shares a 360-kilometre (224 mi) land boundary with the Republic of Ireland.
The United Kingdom has a temperate climate, with plentiful rainfall all year round.The temperature varies with the seasons but seldom drops below −10 °C (14.0 °F) or rises above 35 °C (95 °F). The prevailing wind is from the southwest, bearing frequent spells of mild and wet weather from the Atlantic Ocean. Eastern parts are most sheltered from this wind and are therefore the driest. Atlantic currents, warmed by the Gulf Stream, bring mild winters, especially in the west, where winters are wet, especially over high ground. Summers are warmest in the south east of England, being closest to the European mainland, and coolest in the north. Snowfall can occur in winter and early spring, though it rarely settles to great depth away from high ground.
England accounts for just over half of the total area of the UK, covering 130,410 square kilometres (50,350 sq mi). Most of the country consists of lowland terrain, with mountainous terrain north-west of the Tees-Exe line including the Cumbrian Mountains of the Lake District, the Pennines and limestone hills of the Peak District, Exmoor and Dartmoor. The main rivers and estuaries are the Thames, Severn and the Humber. England's highest mountain is Scafell Pike, which is in the Lake District 978 metres (3,209 ft). England has a number of large towns and cities, including six of the top 50 Larger Urban Zones in the European Union.
Scotland accounts for about a third of the total area of the UK, covering 78,772 square kilometres (30,410 sq mi), including nearly eight hundred islands, mainly west and north of the mainland, notably the Hebrides, Orkney Islands and Shetland Islands. The topography of Scotland is distinguished by the Highland Boundary Fault – a geological rock fracture – which traverses the Scottish mainland from Helensburgh to Stonehaven. The faultline separates two distinctively different regions; namely the Highlands to the north and west and the lowlands to the south and east. The more rugged Highland region contains the majority of Scotland's mountainous terrain, including Ben Nevis, which at 1,343 metres (4,406 ft) is the highest point in the British Isles. Lowland areas, especially the narrow waist of land between the Firth of Clyde and the Firth of Forth known as the Central Belt, are flatter and home to most of the population including Glasgow, Scotland's largest city, and Edinburgh, the capital and political centre of the country.
Ben Nevis, in Scotland, is the highest point in the British IslesWales accounts for less than a tenth of the total area of the UK, covering 20,758 square kilometres (8,010 sq mi). Wales is mostly mountainous, though south Wales is less mountainous than north and mid Wales. The main population and industrial areas are in south Wales, consisting of the coastal cities of Cardiff (the capital, political and economic centre), Swansea and Newport and the South Wales Valleys to their north. The highest mountains in Wales are in Snowdonia, and include Snowdon (Welsh: Yr Wyddfa), which, at 1,085 m (3,560 ft) is the highest peak in Wales. The 14 (or possibly 15) Welsh mountains over 3,000 feet (914 m) high are known collectively as the Welsh 3000s. Wales has over 1,200 km (750 miles) of coastline. There are several islands off the Welsh mainland, the largest of which is Anglesey (Ynys Môn) in the northwest.
Northern Ireland accounts for just 14,160 square kilometres (5,470 sq mi) and is mostly hilly. It includes Lough Neagh, at 388 square kilometres (150 sq mi), the largest body of water in the UK and Ireland. The highest peak in Northern Ireland is Slieve Donard at 849 metres (2,785 ft) in the Mourne Mountains.