The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK or U.K.) or Britain, is a sovereign country located off the north­western coast of the European mainland. The United Kingdom includes the island of Great Britain, the north­eastern part of the island of Ireland, and many smaller islands. Northern Ireland shares a land border with the Republic of Ireland. The total area of the United Kingdom is 94,000 square miles (240,000 km2).

The United States of America (USA), commonly known as the United States (U.S. or US) or America, is a country located primarily in North America, consisting of 50 states, a federal district, five major self-governing territories, and various possessions. At 3.8 million square miles (9.8 million square kilometers), it is the world's third- or fourth-largest country by total area.