All Americans learned in school that we fought two wars against the British, namely the American Revolution and the War of 1812, but there was a third war that began in 1859 which has been largely forgotten. Following the War of 1812, the United Kingdom and the United States agreed in the Treaty of Oregon that the boundary between the countries was along the 49th parallel from the Rocky Mountains to the middle of the channel which separates the continent from Vancouver’s Island then south through the channel to the Strait of Juan de Fuca and west to the Pacific Ocean (see map). This agreement was made by using crude maps by people who had little knowledge of the area. Both parties were unaware that there were two distinct channels or straits, the Haro Strait and the Rosario Strait, which were divided by San Juan Island. Because of the way the treaty was written, both countries claimed right to the island and people from both countries began settling on the island. For years, tension rose as each side argued that settlers from the other side were nothing more than squatters or trespassers.
The first shot of the war happened on June 15, 1859, when Lyman Cutlar, an American, shot and killed a British subject whom Lyman had found destroying crops in his field. British authorities threatened to arrest Lyman and to evict all Americans from the island. In response, American Brigadier General William Harney ordered a company of 64 infantry soldiers to the island. When the soldiers arrived, the British Governor at Vancouver ordered Royal Navy Captain Geoffrey Phipps Hornby to take his 31-gun steam frigate HMS Tribune to remove the American soldiers. More British warships joined the Tribune shortly thereafter, and more American soldiers were sent to the island. For months, the British and Americans stockpiled weapons and built up their forces for the upcoming battle. Each side drilled and fired their cannons, but they were careful not to aim at the opposing soldiers just yet. As both sides were making their final preparations for battle, General Winfield Scott, U.S. Army commander and War of 1812 veteran, arrived and began negotiations. General Scott proposed and both sides agreed on a joint military occupation until a final border could be agreed upon. For twelve long, tense years, San Juan Island remained under joint military occupation. In 1871, when Great Britain and the United States were still unable to agree on ownership of San Juan Island, they turned to Kaiser Wilhelm I of Germany who set up a three-man arbitration commission to settle the dispute. Both sides agreed that the commission’s decision would be final. Finally in October 1872, after nearly a year of discussions by the commission, Kaiser Wilhelm I ruled in favor of the United States. San Juan Island belonged to the United States. The Royal Marines withdrew the following month, and the war ended 14 years after the first shot was fired. The war over San Juan Island was named after that British subject who was the only fatality of this war between the United Kingdom and the United States. It is known as the Pig War. That’s right. This conflict between the United Kingdom and United States was set off by a squabble over a pig.
Source: “The Pig War,” National Park Service: San Juan Island, accessed July 19, 2026, https://www.nps.gov/sajh/