In 1775, long-running tensions between colonists in New England and the representatives of the British government exploded into open conflict at Lexington and Concord, Massachusetts.
From this clash between Massachusetts Militia and British Regulars grew a New England Army of Observation that laid siege to Boston and on June 14, 1775, officially become the Continental Army. While conflict was not inevitable in 1775, it grew more likely as tensions rose that spring.