The United Kingdom consists of the island of Great Britain, the northeastern part of the island of Ireland, and many smaller islands (such as the Hebrides, Shetland, Orkney, the Isle of Wight, and Anglesey). It is surrounded by the Atlantic Ocean, with the North Sea to the east, the English Channel to the south, and the Celtic Sea to the southwest. The Irish Sea separates Great Britain and Ireland. This insular geography has heavily influenced the nation's historical defense strategies and its maritime culture.
The country's physical geography is highly varied. England features rolling plains, gentle hills, and meandering rivers like the Thames, Severn, and Trent. Scotland is defined by its rugged highlands, deep freshwater lochs (such as Loch Ness and Loch Lomond), and heavily indented coastline. Wales is highly mountainous, dominated by the Cambrian Mountains and Snowdonia. Northern Ireland features the basalt columns of the Giant's Causeway and the expansive Lough Neagh, the largest lake in the British Isles.
Natural resources have historically played a vital role in the UK's development. Plentiful coal and iron ore deposits fueled the Industrial Revolution, while the late 20th century saw the exploitation of substantial oil and natural gas reserves in the North Sea. Today, the geography of the coastline and offshore waters is increasingly utilized for large-scale wind energy production.