June 7 - Tudor Vladimirescu, Romanian rebellion-leader (b. cca. 1780)
June 17 - Martín Miguel de Güemes Argentine military leader, (b. 1785)
March 21 - First revolutionary act in Monastery of Agia Lavra, Kalavryta, Greek War of Independence.
March 23 - Battle and fall of city of Kalamata, Greek War of Independence.
March 25 - (Julian Calendar) Greeks revolt against the Ottoman Empire, beginning the Greek War of Independence.
May 8 - Greek War of Independence: The Greeks defeat the Turks in Gravia.
May 12 - The first big battle of the Greek War of Independence against the Turks occurs in Valtetsi.
June 14 - Badi VII, king of Sennar, surrenders his throne and realm to Ismail Pasha, general of the Ottoman Empire, ending the existence of that Sudanese kingdom.
June 19 - Decisive defeat of the Philikí Etaireía by the Ottomans at Drăgăşani (in Wallachia).
June 24 - The Battle of Carabobo takes place. It is the decisive battle in the war of independence of Venezuela from Spain.
July 10 - The United States takes possession of its newly bought territory of Florida from Spain.
July 28 - José de San Martín declares independence for Peru from Spain.
August 4 - Atkinson & Alexander publish the Saturday Evening Post for the first time as a weekly newspaper.
August 10 - Missouri is admitted as the 24th U.S. state.
August 21 - Jarvis Island is discovered by the crew of the ship, Eliza Frances.
August 24 - The Treaty of Córdoba is signed in Córdoba, now in Veracruz, Mexico, concluding the Mexican War of Independence from Spain.
September 7 - The Republic of Gran Colombia (a federation covering much of present day Venezuela, Colombia, Panama, and Ecuador) was established, with Simón Bolívar as the founding President and Francisco de Paula Santander as vice president.
September 15 - Guatemala, El Salvador, Honduras, Nicaragua, and Costa Rica jointly declare independence from Spain.
September 23 - Tripolitsa, Greece, falls and 30,000 Turks are massacred.