The British Empire comprised the dominions, colonies, protectorates, mandates and other territories ruled or administered by the United Kingdom. It originated with the overseas colonies and trading posts established by England in the late 16th and early 17th centuries. At its height, it was the largest empire in history and, for over a century, was the foremost global power. By 1922 the British Empire held sway over about 458 million people, one-fifth of the world's population at the time, and covered more than 33,700,000 km² (13,012,000 sq mi), almost a quarter of the Earth's total land area. As a result, its political, linguistic and cultural legacy is widespread. At the peak of its power, it was often said that "the sun never sets on the British Empire" because its span across the globe ensured that the sun was always shining on at least one of its numerous territories.

During the Age of Discovery in the 15th and 16th centuries, Portugal and Spain pioneered European exploration of the globe, and in the process established large overseas empires. Envious of the great wealth these empires generated, England, France and the Netherlands began to establish colonies and trade networks of their own in the Americas and Asia. A series of wars in the 17th and 18th centuries with the Netherlands and France left England (and then, following union between England and Scotland in 1707, Great Britain) the dominant colonial power in North America and India. The loss of the Thirteen Colonies in North America in 1783 after a war of independence deprived Britain of some of its oldest and most populous colonies.

The term British Indian (also Indian British or Indian Britons) refers to citizens of the United Kingdom whose ancestral roots lie in India. This includes people born in the UK who are of Indian descent, and Indian-born people who have migrated to the UK. Today, Indians number around one and a half million in the UK (not including those of mixed Indian and Other ancestry), making them the single largest visible ethnic minority population in the country. They make up the largest subgroup of British Asians, and are one of the largest Indian communities in the Indian diaspora, largely due to the Indian-British relations (including historical links such as India having been under British occupation and still being part of the Commonwealth of Nations). The British Indian community is the fifth largest in the Indian diaspora, behind the Indian communities in Nepal, the United States, Malaysia and Burma.

British Indians are a well established and middle class ethnic group. A study by the Joseph Rowntree Foundation in 2007 found British Indians have among the lowest poverty rates among different ethnic groups in Britain second only to White British.

An Indian Colony is a Native American settlement associated with an urban area. Although some of them become official Indian reservations, they differ from most reservations in that they are located where Native Americans could find employment in mainstream American economy. Many were originally formed without federal encouragement or sanction.

Indian colonies are especially common in Nevada. As the Great Basin ecosystem is very fragile, native lifeways became untenable soon after white settlement due to livestock over-grazing, water diversions and the felling of Pinyon pine groves. At that time there were few official reservations in the area, and those were terribly run even by contemporary standards. Many Native Americans chose instead to seek jobs in white ranches, farms and cities. The areas in which they settled became known as Indian Camps or Colonies. In some cases they owned the land they settled on, in other cases they settled on public land. Starting in the early twentieth century, the federal government began establishing Indian trust territories for the colonies on public land.

British Americans are citizens of the United States whose ancestry originates wholly or partly in the United Kingdom (England, Wales, Scotland and Northern Ireland). The term is seldom used by people to refer to themselves (1,172,050 chose it in the 2009 American Community Survey) and is used primarily as a demographic or historical research term. In the modern age, it can refer to British people who live and work in the United States (some of whom become American citizens), and Americans who do the same in the United Kingdom.

According to American Community Survey in 2009 data, Americans reporting British ancestry made up an estimated (40,234,652) or 13.0% of the total U.S. population, and form the third largest European ancestry group after German Americans and Irish Americans. This is an approx 35% drop from the population figures derived from the 1980 United States Census.

However, demographers regard this as an undercount as the index of inconsistency is high, and many, if not most, people from English stock have a tendency to identify simply as Americans or, if of mixed European ancestry, nominate a more recent and differentiated ethnic group. Consequently, many well-established white Americans have at least some British ancestry^{[citation needed]}, including many who identify primarily with other ethnic groups (such as Irish, German, Scandinavian, and so forth).