On this day, June 15, in 1859

The Pig War began on San Juan Island when an American settler shot a British pig. An earlier treaty dividing the Oregon Country between Britain and the US had left possession of the small island off the coast of Washington state very unclear, and tension was high as people from both countries began to settle there. When British authorities threatened to arrest the American responsible for the shooting, he immediately requested US military protection. Each side began sending troops to the island, until there were almost 500 American soldiers and over 2000 British ones. Eventually the both sides decreased their troops, but joint occupation continued for 12 years until the land was granted to the US.