In 1859, a tense boundary dispute between the United States and Great Britain on San Juan Island escalated into a military standoff known as the Pig War. The conflict began when an American farmer shot a British-owned pig eating his potatoes. Both nations deployed troops and warships to the island. Fortunately, local commanders maintained their cool, and the only casualty of the entire confrontation was the original pig.
An Ambiguous Treaty in the Pacific Northwest
In June 1846, the United States and Great Britain signed the Oregon Treaty to resolve competing territorial claims in the Pacific Northwest. The agreement established the 49th parallel as the international boundary from the Rocky Mountains westward to the Pacific coast. However, geography complicated the line once it reached the water. To avoid dividing Vancouver Island, negotiators agreed the boundary would follow the middle of the channel separating Vancouver Island from the continent, and then proceed southward through the middle of the channel and the Strait of Juan de Fuca to the open ocean.
The treaty drafters relied on incomplete maps and failed to specify which channel constituted the main passage. In the waters between Vancouver Island and mainland Washington lay the San Juan Islands, bounded by two primary waterways: Haro Strait to the west and Rosario Strait to the east. The United States claimed Haro Strait as the intended boundary, which placed the entire San Juan archipelago on the American side. Great Britain argued for Rosario Strait, placing the islands under British dominion. Because both nations asserted sovereignty, both allowed their citizens to settle on the largest landmass, San Juan Island.
The Potato Patch Confrontation
By the late 1850s, San Juan Island hosted two distinct communities living alongside one another. The Hudson's Bay Company established the Belle Vue Sheep Farm on the southern portion of the island, managed by Charles Griffin, an Irish employee of the company. Around the same time, roughly two dozen American settlers arrived to establish homesteads under the United States Donation Land Claim Act, viewing the British presence as unauthorized squatting on American soil.
On June 15, 1859, an American farmer named Lyman Cutlar discovered a large black boar rooting through his garden and eating his potatoes. Having chased the animal away on previous occasions, Cutlar lost his temper and shot the pig, killing it. When Cutlar learned the pig belonged to Griffin, he visited the farm manager to apologize and offered ten dollars in compensation. Griffin rejected the offer, demanding one hundred dollars instead. Cutlar rescinded his offer, stating that the pig had been trespassing on his crop. When British colonial authorities threatened to arrest Cutlar under British law, the American settlers drafted a petition requesting military protection from the United States Army.
Military Mobilization on San Juan Island
The petition reached Brigadier General William S. Harney, commander of the Department of Oregon. Harney, known for his aggressive anti-British views, acted swiftly without consulting his superiors in Washington, D.C. On July 27, 1859, he dispatched Captain George Pickett—who would later gain fame in the American Civil War—along with sixty-six soldiers of the 9th US Infantry to establish a garrison on San Juan Island. Pickett landed near Griffin's sheep farm, raised the American flag, and issued an order declaring that only American law applied on the island.
The British colonial administration in nearby Victoria reacted with alarm. James Douglas, the Governor of Vancouver Island and British Columbia, ordered three British warships under the command of Captain Geoffrey Hornby to sail to Griffin Bay. Douglas instructed the naval force to land British troops on the island and confront the American detachment. The situation escalated rapidly as Pickett refused to withdraw, declaring his intention to resist any British landing even if vastly outnumbered.
Cool Heads and Restraint at Sea
Despite Governor Douglas's orders, the British naval commanders exercised remarkable restraint. Rear Admiral Robert L. Baynes, commander of the British Pacific Station, arrived aboard his flagship and assessed the confrontation. Baynes flatly refused Douglas's instructions to land marines and engage Pickett's forces. He famously observed that engaging two great world powers in a war over a dispute about a pig was completely foolish and unjustified.
Captain Hornby maintained a strict policy of non-engagement while the standoff persisted. Over the following weeks, General Harney dispatched substantial reinforcements under Colonel Silas Casey. By August 1859, the American force on San Juan Island had grown to 461 infantrymen, engineers, and artillerymen equipped with fourteen cannons. Surrounding the island were five British warships carrying 167 guns and more than two thousand sailors and Royal Marines. Despite the overwhelming firepower gathered in the small bay, officers on both sides maintained open communication and strictly ordered their men never to fire unless fired upon.
The Joint Military Occupation
News of the standoff traveled across the continent and across the Atlantic, causing deep concern in both Washington and London. Neither President James Buchanan nor the British Prime Minister, Lord Palmerston, had any desire to enter an armed conflict over an isolated island territory. President Buchanan immediately dispatched Lieutenant General Winfield Scott, the senior commander of the United States Army and a seasoned diplomat, to de-escalate the crisis.
General Scott arrived in the Pacific Northwest in October 1859 and opened direct negotiations with Governor Douglas. The two leaders quickly reached a compromise: both nations agreed to withdraw the bulk of their forces and maintain a joint military occupation until a permanent diplomatic settlement could be reached. The agreement limited each country's garrison to no more than one hundred men. The Americans occupied a fortification at the southern end of the island, known as American Camp, while the British Royal Marines established a station at the northern end, known as English Camp. For the next twelve years, the opposing garrisons lived amicably, sharing holiday celebrations, athletic contests, and social gatherings.
Arbitration and Final Settlement
The onset of the American Civil War in 1861 diverted attention from the boundary dispute, leaving the joint occupation in place for over a decade. It was not until the Treaty of Washington in 1871 that the United States and Great Britain agreed to resolve several outstanding disputes, including the San Juan water boundary. The treaty submitted the boundary question to international arbitration, appointing Kaiser Wilhelm I of Germany to act as the sole arbitrator.
A panel of international legal and geographic experts reviewed the historical claims, treaty texts, and navigational charts for a year. On October 21, 1872, the German commission ruled in favor of the United States, concluding that Haro Strait was the primary channel intended by the 1846 treaty. Great Britain formally accepted the ruling, and on November 25, 1872, the Royal Marines peacefully evacuated English Camp. The Pig War ended without a single shot fired between the opposing armies, leaving the unfortunate pig as the conflict's sole casualty.
Key takeaways
•The 1859 Pig War arose from an ambiguous clause in the 1846 Oregon Treaty, which left ownership of the San Juan Islands unresolved between the US and Great Britain.
•The standoff was triggered when American settler Lyman Cutlar shot a British-owned pig rooting in his potato patch, prompting military mobilizations on both sides.
•British naval commanders, notably Rear Admiral Robert L. Baynes, averted war by refusing colonial orders to land troops against Captain George Pickett's American forces.
•The confrontation led to a peaceful twelve-year joint occupation, concluded in 1872 when German Emperor Wilhelm I arbitrated the boundary in favor of the United States.