TJ Lacey By tj.lacey Apr 19, 1775 Battle at Lexington & Concord, Massachusetts Period: Apr 19, 1775 to Sep 3, 1783 American Revolution Jul 4, 1776 Decloration of Independence signed Dec 19, 1777 Valley Forge Washington's army established headquarters at Valley Forge. Feb 6, 1778 US and France enter a military alliance Oct 19, 1781 Cornwallis surrenders at Yorktown, Virginia Sep 3, 1783 Treaty of Paris signed Period: Apr 12, 1861 to Apr 9, 1865 Civil War