Young's interference experiment — 1801 double-slit optical experiment by Thomas Young

Treaty signed in 1801 between John VI of Portugal and representatives from the French Republic

1801 treaty between Great Britain and Persia

Treaty of Lunéville — 1801 Treaty during the War of the Second Coalition

1801 minor naval engagement during the French Revolutionary Wars

1801 second battle of the French campaign in Egypt and Syria to be fought at Abu Qir

1801 battle during the French Campaign in Egypt and Syria

1801 treaty between France and Spain

1801 battle during the French Campaign in Egypt and Syria

1801 siege during the French Campaign in Egypt and Syria

Battle between British and Dano–Norwegian navies (1801)