- Jun 4 Louisiana Territory officially renamed "Missouri Territory"
Assassination of Spencer Perceval
Jun 8 Robert Jenkinson becomes Prime Minister of the United Kingdom after Spencer Perceval's assassination
- Jun 18 War of 1812 begins as US declares war against Britain
Victory in Battle
Jun 22 Upon learning of plans by the Americans to execute a surprise attack, Laura Secord walks 32 km to warn British troops, results in a British surprise victory at the Battle of Beaver Dams