The Battles of Lexington an Concord were the first military engagements of the American Revolutionary War. They were fought on April 19, 1775, in Middlesex County, Province of Massachusetts Bay, within the towns of Lexington, Concord, Lincoln, Menotomy (present-day Arlington), and Cambridge, near Boston. The battles marked the outbreak of open armed conflict between the Kingdom of Great Britain and its thirteen colonies in the mainland of British North America.