1804

Events from the year 1804 in the United States.
==Incumbents==
===Federal Government===
* President: Thomas Jefferson (DR-VA)
* Vice President: Aaron Burr (DR-NY)
* Chief Justice: John Marshall (VA)
* Speaker of the House of Representatives: Nathaniel Macon (DR-NC)
* Congress: 8th
==Events==
===January - March===
* February 15 – New Jersey becomes the last northern state to abolish slavery.
* February 16 – First Barbary War: Stephen Decatur leads a raid to burn the pirate-held frigate Philadelphia.
* February 18 – Ohio University is chartered by the Ohio General Assembly.
* March 10 – Last formalities of the Louisiana Purchase; in St. Louis, a ceremony is conducted to transfer ownership from France to the United States.
* March 26 – Orleans Territory is created.
===April - June===
* May 14 – The Lewis and Clark Expedition departs from Camp Dubois and begins their historic journey by traveling up the Missouri River.
* June 15 – The 12th Amendment to the United States Constitution is ratified by New Hampshire, and arguably becomes effective (subsequently vetoed by the Governor of New Hampshire).
===July - September===
* July 11 – Burr-Hamilton duel: Alexander Hamilton is shot during a duel with Aaron Burr and dies the next day.
* July 27 – The 12th Amendment to the United States Constitution is ratified by Tennessee, removing doubt surrounding adoption.
* August 20 – Lewis and Clark Expedition: The Corps of Discovery, whose purpose is to explore the Louisiana Purchase, suffers its only death when Sergeant Charles Floyd dies, apparently from acute appendicitis.
* August 26 – Lewis and Clark Expedition: The first election west of the Mississippi River is held. Patrick Gass is elected Sergeant replacing Charles Floyd.
===October - December===
* October 1 – Orleans Territory is effective.
* October 24 – Lewis and Clark Expedition: The Expedition encounter the Mandan and Hidatsa tribes, for the first time, near present-day Washburn, North Dakota. They decide to build Fort Mandan their winter quarters near the main village.
* November 3 – The Treaty of St. Louis is signed by Quashquame and William Henry Harrison; controversy surrounding the treaty eventually causes the Sauks to ally with the British during the War of 1812 and is the main cause of the Black Hawk War of 1832.
* November 30 – The Democratic-Republican-controlled United States Senate begin an impeachment trial against Federalist-partisan Supreme Court of the United States Justice Samuel Chase (he was charged with political bias but was acquitted by the United States Senate of all charges on March 1, 1805).
* December 3 – Thomas Jefferson defeats Charles C. Pinckney in the U.S. presidential election.
==Memoriam==
* January 11 – James Tytler, editor of Encyclopædia Britannica (aged 59; Salem, MA, USA)
* February 2 – George Walton, signer of the Declaration of Independence (aged 55; Augusta, GA, USA)
* April 16 – William Maclay, United States Senator from Pennsylvania from 1789 to 1791 (aged 66; Dauphin, PA, USA)
* July 12 – Alexander Hamilton, a Founding Father of the United States, founder of the nation's financial system, founder of the Federalist Party, statesman (killed in a duel with Aaron Burr) (aged 49; Manhattan, NY, USA)
* August 6 – Abraham Wood, composer (aged 52; Northborough, MA, USA)
* August 20 – Charles Floyd, explorer, only fatality of the Lewis and Clark Expedition (aged 22; LA Territory (Now IA), USA)
* September 4 – Richard Somers, naval officer (killed in battle) (aged 25; Tripoli, Libya)
* September 29 – Michael Hillegas, 1st Treasurer of the United States (aged 75; Philadelphia, PA, USA)
* November 18 – Philip Schuyler, general in the American Revolution, United States Senator from New York, father of wife of Alexander Hamilton, Elizabeth Schuyler Hamilton (aged 70; Albany, NY, USA)
==External links==
* 1804 in the United States
Category:United States History: Volume 3