The Oregon Treaty of 1846 aimed to settle the Pacific Northwest border between British North America and the United States, specifying that the line should run through the middle of the channel separating Vancouver Island from the mainland. However, the treaty neglected to specify whether it meant the Haro Strait on the west or the Rosario Strait on the east, leaving San Juan Island directly in disputed territory. Both American settlers and the British Hudson's Bay Company established operations on the island, living side by side in tense harmony until June 15, 1859.
On that fateful day, American farmer Lyman Cutlar found a large black pig belonging to British sheep rancher Charles Griffin rooting around in his potato patch and shot it dead. When British authorities threatened to arrest Cutlar, American settlers requested military protection. Captain George Pickett—who later gained fame in the American Civil War—arrived with 66 U.
S. soldiers, setting up camp on the island and declaring it American territory. Outraged, British Governor James Douglas dispatched three warships under Royal Navy Captain Geoffrey Hornby with orders to dislodge the Americans.
Hornby wisely refused to open fire over a farm animal dispute, preventing an immediate military escalation. When news reached Washington and London, leaders on both sides were appalled that a pig had brought two nations to the edge of war. General Winfield Scott was dispatched to negotiate a joint military occupation, which lasted peacefully for 12 years until Kaiser Wilhelm I of Germany arbitrated the treaty in 1872, awarding the island to the United States.