In the 19th century, the US and UK were disputing on how to divide the Pacific Northwest of North America.
The Oregon Treaty in 1846 established the border between American’s Oregon Country and Britain’s Columbia District along the 49th parallel of north latitude.
The border, which separated Vancouver Island from the mainland, ran straight through the San Juan Islands, with both the US and UK claiming sovereignty over them.
Thirteen years after the treaty’s creation, this ambiguity led to conflict.
The Hudson Bay Company, who administered most of the British presence in the region, had established a sheep farm on San Juan Island.
Meanwhile, American farmers had also begun to settle on the disputed land.
Things came to a head when one of these farmers, Lyman Cutler, shot a pig owned by a Hudson Bay employee after he found it eating his potatoes.
When the sum of compensation could not be agreed, British authorities threatened to arrest Cutler, who then called for US military protection.
In response, 66 American soldiers of the 9th Infantry Regiment sailed to the island with orders to prevent the British from landing.
To counter this, three British warships were deployed to the region.
An American camp was established at the south end of San Juan Island, while Royal Marines manned the British camp in the north.
The situation continued to escalate.
By 10 August 1859, 461 Americans with 14 cannons were opposed by five British warships mounting 70 carrying guns and 2,140 men aboard.
However, local commanders on both sides had been given the same orders, to defend themselves but not fire the first shot.
The standoff continued with both sides trading insults, but discipline held and no shots were fired.
It took six weeks for the news to reach Washington DC and London, where officials on both sides were shocked to learn of the unfolding crisis and took swift action to defuse the potentially explosive international incident.
In September, US President James Buchanan was dealing with a nation on the edge of civil war, so sent General Winfield Scott to negotiate with Governor Douglas to resolve the stalemate.
Following negotiations, both sides agreed to share military occupation of the island until a final solution could be found.
Both sides limited their token task forces to 100 men.
The joint occupation held for the next 12 years, while the American Civil War played out.
But, by 1871, the US and Britain agreed that a resolution needed to be found.
The issue was submitted to the German Emperor William I for binding arbitration, the first time this had happened in modern western history.
He found in favour of the US, placing the San Juan Islands within their territory, so ending the bloodless Pig War.
On 25 November 1872, the British withdrew their Royal Marines from the British camp, with the Americans following by July 1874.
Cover image: PA.