1770 Boston Massacre: British troops fire into a mob, killing five men and leading to intense public protests.
1773 Boston Tea Party: Group of colonial patriots disguised as Mohawk Indians board three ships in Boston harbor and dump more than 300 crates of tea overboard as a protest against the British tea tax.
1774 First Continental Congress meets in Philadelphia, with 56 delegates representing every colony except Georgia. Delegates include Patrick Henry, George Washington, and Samuel Adams.
1775–1783American Revolution: War of independence fought between Great Britain and the 13 British colonies on the eastern seaboard of North America. Battles of Lexington and Concord, Mass., between the British Army and colonial minutemen, mark the beginning of the war. Battle-weary and destitute Continental army spends brutally cold winter and following spring at Valley Forge, Pa. British general Charles Cornwallis surrenders to Gen. George Washington at Yorktown, Va. Great Britain formally acknowledges American independence in the Treaty of Paris.
1776 Continental Congress adopts the Declaration of Independence in Philadelphia.
1777 Continental Congress approves the first official flag of the United States. Continental Congress adopts the Articles of Confederation, the first U.S. constitution.
1786 Shays's Rebellion erupts; farmers from New Hampshire to South Carolina take up arms to protest high state taxes and stiff penalties for failure to pay.
1787 Constitutional Convention, made up of delegates from 12 of the original 13 colonies, meets in Philadelphia to draft the U.S. Constitution.
1789 George Washington is unanimously elected president of the United States in a vote by state electors. U.S. Constitution goes into effect, having been ratified by nine states.
1790 U.S. Supreme Court meets for the first time at the Merchants Exchange Building in New York City.
1791 First ten amendments to the Constitution, known as the Bill of Rights, are ratified.
1793 Washington's second inauguration is held in Philadelphia. Eli Whitney's invention of the cotton gin greatly increases the demand for slave labor.
1797 John Adams is inaugurated as the second president in Philadelphia.
1800 The U.S. capital is moved from Philadelphia to Washington, DC.
1801 Thomas Jefferson is inaugurated as the third president in Washington, DC.
1803 Louisiana Purchase: United States agrees to pay France $15 million for the Louisiana Territory, which extends west from the Mississippi River to the Rocky Mountains.
1804 Lewis and Clark set out from St. Louis, Mo., on expedition to explore the West and find a route to the Pacific Ocean.
1805 Jefferson's second inauguration. Lewis and Clark reach the Pacific Ocean.
1809 James Madison is inaugurated as the fourth president.
1812–1814 War of 1812: U.S. declares war on Britain over British interference with American maritime shipping and westward expansion. British capture Washington, DC, and set fire to White House and Capitol. Francis Scott Key writes Star-Spangled Banner as he watches British attack on Fort McHenry at Baltimore. Treaty of Ghent is signed, officially ending the war.
1817 James Monroe is inaugurated as the fifth president.
1819 Spain agrees to cede Florida to the United States.
1820 Missouri Compromise: In an effort to maintain the balance between free and slave states, Maine (formerly part of Massachusetts) is admitted as a free state so that Missouri can be admitted as a slave state; except for Missouri.
