Events of 1809

January - March

• January 5 - Treaty of the Dardanelles between Britain and the Ottoman Empire concluded.
• January 10 - French Marshal Jean Lannes begins the Siege of Zaragoza.
• January 16 - Peninsular War: The French defeat the British at the Battle of Corunna.
• February 3 - Illinois Territory was created.
• February 8 - Franz I of Austria declares war on France,
• February 11 - Robert Fulton patents the steamboat.
• February 20 - A decision by the Supreme Court of the United States states that the power of the federal government is greater than any individual state.
• February 20 - Siege of Zaragoza grinds to a halt as Jose Palafox surrenders. Over 60,000 had been killed on both sides in 41 days of street fighting.
• February 25 - Spanish forces are defeated at the Battle of Valls in Catalonia by Marshal Laurent Gouvion Saint-Cyr.
• March 1 - Embargo Act repealed, Non-Intercourse Act replaces it.
• March 4 - James Madison succeeds Thomas Jefferson as the President of the United States.
• March 13 - Military coup ousts Gustav IV Adolf of Sweden - he's confined in the Gripsholm Castle.
• March 29 - At the Diet of Porvoo, Finland's four Estates pledge allegiance to Alexander I of Russia, commencing the secession of the Grand Duchy of Finland from Sweden. King Gustav IV Adolf of Sweden abdicates after a coup d'état and is later exiled.
• March 29 - The First Battle of Porto ends in disaster as 18,000 Portuguese soldiers are drowned in a rout after defeat by the French under Marshal Soult and the Battle of Medellín results in massive Spanish casualties in Extremadura, when Marshal Victor's cavalry routs their army.

April - June