September 11, 1803
1803 treaty between the United States and Native Americans
Louisiana Purchase — 1803 acquisition by the U.S. of France's claim to the territory of Louisiana
1803 naval battle between the United States and the Tripoli Eyalet
1803 marked the opening shots of the Blockade of Saint-Domingue
1803 treaty between the United States and the Kaskaskia
1803 treaty between the United States and Choctaw
1803 battle of the Second Anglo-Maratha War
1803 major battle of the Second War of Haitian Independence
1803 treaty between Great Britain and Maratha