The Kingdom of Great Britain (officially Great Britain) was a sovereign country in Western Europe from 1 May 1707 to the end of 31 December 1800. The state was created by the 1706 Treaty of Union and ratified by the Acts of Union 1707, which united the kingdoms of England (which included Wales) and Scotland to form a single kingdom encompassing the whole island of Great Britain and its outlying islands, with the exception of the Isle of Man and the Channel Islands. The unitary state was governed by a single parliament at the Palace of Westminster, but distinct legal systems English law and Scots law remained in use.

The formerly separate kingdoms had been in personal union since the 1603 "Union of the Crowns" when James VI of Scotland became King of England and King of Ireland. Since James's reign, who had been the first to refer to himself as "king of Great Britain", a political union between the two mainland British kingdoms had been repeatedly attempted and aborted by both the Parliament of England and the Parliament of Scotland. Queen Anne (r. 17021714) did not produce a clear Protestant heir and endangered the line of succession, with the laws of succession differing in the two kingdoms and threatening a return to the throne of Scotland of the Roman Catholic House of Stuart, exiled in the Glorious Revolution of 1688.

The resulting kingdom was in legislative and personal union with the Kingdom of Ireland from its inception, but the Parliament of Great Britain resisted early attempts to incorporate Ireland in the political union. The early years of the newly united kingdom were marked by Jacobite risings, particularly the Jacobite rising of 1715. The relative incapacity or ineptitude of the Hanoverian kings resulted in a growth in the powers of Parliament and a new role, that of "prime minister", emerged in the heyday of Robert Walpole. The "South Sea Bubble" economic crisis was brought on by the failure of the South Sea Company, an early joint-stock company. The campaigns of Jacobitism ended in defeat for the Stuarts' cause in 1746.

The Hanoverian line of monarchs gave their names to the Georgian era and the term "Georgian" is typically used in the contexts of social and political history for Georgian architecture. The term "Augustan literature" is often used for Augustan drama, Augustan poetry and Augustan prose in the period 17001740s. The term "Augustan" refers to the acknowledgement of the influence of classical Latin from the ancient Roman Republic.Victory in the Seven Years' War led to the dominance of the British Empire, which was to become the foremost global power for over a century. Great Britain dominated the Indian subcontinent through the trading and military expansion of the East India Company in colonial India. In wars against France, it gained control of both Upper and Lower Canada, and until suffering defeat in the American War of Independence, it also had dominion over the Thirteen Colonies. From 1787, Britain began the colonisation of New South Wales with the departure of the First Fleet in the process of penal transportation to Australia. Britain was a leading belligerent in the French Revolutionary Wars.

Great Britain was merged into the United Kingdom of Great Britain and Ireland on 1 January 1801, with the Acts of Union 1800, enacted by Great Britain and Ireland, under George III, to merge with it the Kingdom of Ireland.

The American Revolutionary War (April 19, 1775 – September 3, 1783), also known as the Revolutionary War or American War of Independence, secured a United States of America independent from Great Britain. Fighting began on April 19, 1775, followed by the Declaration of Independence on July 4, 1776. The American Patriots were supported by France and Spain, conflict taking place in North America, the Caribbean, and Atlantic Ocean. It ended on September 3, 1783 when Britain accepted American independence in the Treaty of Paris, while the Treaties of Versailles resolved separate conflicts with France and Spain.Established by Royal charter in the 17th and 18th centuries, the American colonies were largely autonomous in domestic affairs and commercially prosperous, trading with Britain and its Caribbean colonies, as well as other European powers via their Caribbean entrepôts. After British victory in the Seven Years' War in 1763, tensions arose over trade, colonial policy in the Northwest Territory and taxation measures, including the Stamp Act and Townshend Acts. Colonial opposition led to the 1770 Boston Massacre and 1773 Boston Tea Party, with Parliament responding by imposing the so-called Intolerable Acts.

On September 5, 1774, the First Continental Congress drafted a Petition to the King and organized a boycott of British goods. Despite attempts to achieve a peaceful solution, fighting began with the Battle of Lexington on April 19, 1775 and in June Congress authorized George Washington to create a Continental Army. Although the "coercion policy" advocated by the North ministry was opposed by a faction within Parliament, both sides increasingly viewed conflict as inevitable. The Olive Branch Petition sent by Congress to George III in July 1775 was rejected and in August Parliament declared the colonies to be in a state of rebellion.

Following the loss of Boston in March 1776, Sir William Howe, the new British commander-in-chief, launched the New York and New Jersey campaign. He captured New York City in November, before Washington won small but significant victories at Trenton and Princeton, which restored Patriot confidence. In summer 1777, Howe succeeded in taking Philadelphia, but in October a separate force under John Burgoyne was forced to surrender at Saratoga. This victory was crucial in convincing powers like France and Spain an independent United States was a viable entity.

France provided the US informal economic and military support from the beginning of the rebellion, and after Saratoga the two countries signed a commercial agreement and a Treaty of Alliance in February 1778. In return for a guarantee of independence, Congress joined France in its global war with Britain and agreed to defend the French West Indies. Spain also allied with France against Britain in the Treaty of Aranjuez (1779), though it did not formally ally with the Americans. Nevertheless, access to ports in Spanish Louisiana allowed the Patriots to import arms and supplies, while the Spanish Gulf Coast campaign deprived the Royal Navy of key bases in the south.

This undermined the 1778 strategy devised by Howe's replacement, Sir Henry Clinton, which took the war into the Southern United States. Despite some initial success, by September 1781 Cornwallis was besieged by a Franco-American force in Yorktown. After an attempt to resupply the garrison failed, Cornwallis surrendered in October, and although the British wars with France and Spain continued for another two years, this ended fighting in North America. In April 1782, the North ministry was replaced by a new British government which accepted American independence and began negotiating the Treaty of Paris, ratified on September 3, 1783.