Battle of Concord. The Battles of Lexington and Concord, fought on April 19, 1775, were the first military engagements of the American Revolutionary War. 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. The first shots were fired just as the sun was rising at Lexington. The militia were outnumbered and fell back, and the regulars proceeded on to Concord, where they searched for the supplies. At the North Bridge in Concord, approximately 500 militiamen fought and defeated three companies of the King's troops. The outnumbered regulars fell back from the minutemen after a pitched battle in open territory.