What event opened the major fighting of the American Revolutionary War in April 1775?

The Battles of Lexington and Concord opened the major fighting of the American Revolutionary War on April 19, 1775.

British regulars marched from Boston toward Concord to seize colonial military supplies. Patriot militia confronted them first at Lexington, where shots were fired under circumstances still debated by historians. The British continued to Concord, but colonial forces resisted at the North Bridge and attacked the returning troops along the road to Boston.

The clashes were the first major military actions between British forces and Patriot militias in the thirteen colonies. They followed years of political conflict, including disputes over taxation, representation, and the Intolerable Acts. The fighting transformed a political crisis into an armed rebellion. The Second Continental Congress later appointed George Washington commander-in-chief, and the conflict eventually led to the Declaration of Independence in 1776.