Pig War
1859 CE.
Shown on the map at 48.462°, -123.007°.
The Pig War was a confrontation in 1859 between the United States and the United Kingdom over the British–U.S. border in the San Juan Islands, between Vancouver Island (present-day Canada) and the Washington Territory (present-day State of Washington). The Pig War, so called because it was triggered by the shooting of a pig, is also called the Pig Episode, the Pig and Potato War, the San Juan Boundary Dispute, and the Northwestern Boundary Dispute. Despite being referred to as a "war", there were no human casualties on either side, only a pig.
Text from the Wikipedia article Pig War (1859), licensed CC BY-SA 4.0.