The Vermont Republic (French: Rpublique du Vermont), officially known at the time as the State of Vermont (French: tat du Vermont), was an independent state in New England that existed from January 15, 1777, to March 4, 1791. The state was founded in January 1777, when delegates from 28 towns met and declared independence from the jurisdictions and land claims of the British colonies of Quebec, New Hampshire, and New York. The republic remained in existence for the next fourteen years, albeit without diplomatic recognition from any foreign power. On March 4, 1791, it was admitted into the United States as the State of Vermont, with the constitution and laws of the independent state continuing in effect after admission.The delegates also forbade slavery within their republic. Many Vermonters took part in the American Revolution, but the Continental Congress did not recognize the jurisdiction's independence. Because of objections from New York, which had conflicting property claims, the Continental Congress declined to recognize Vermont, then sometimes also known as the New Hampshire Grants. Vermont's overtures to join the Province of Quebec were accepted by the British, offering generous terms for the Republic's reunion. When the British surrendered at the Siege of Yorktown in 1781, however, American independence became apparent. Vermont, now bordered on three sides by American territory, ended negotiations with the British and instead negotiated terms to become part of the United States.Many of its citizens favored political union with the United States rather than full independence. Both popular opinion and the legal construction of the government made clear that the independent State of Vermont would eventually join the original 13 states. While the Continental Congress did not allow a seat for Vermont, Vermont engaged William Samuel Johnson, representing Connecticut, to promote its interests. In 1785 the Vermont General Assembly granted Johnson title to the former King's College Tract as a form of compensation for representing Vermont.

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.