San Juan Island on the northern edge of the Puget Sound is the site of one of the weirdest international incidents in American history. Two nations, confirmed adversaries, squared off for armed confrontation on this tiny island in 1859. Sloops of war sailed into harbor and positioned their guns. Camps were built and battle lines were drawn. Soldiers drilled in the rain and prepared for battle. Their cause? A British pig that couldn't be kept from eating American potatoes.

As Americans moved west along the Oregon Trail and settled in Washington, the British started to get cagey about the new residents in the area. The existing law of the land had called for joint occupation by Americans and British, a right that the Hudson’s Bay Company had taken full advantage of, conducting trapping and trading operations throughout the Northwest. This arrangement had outlived its usefulness, however, and both sides met in 1849 to thresh out a more permanent solution. The resulting Oregon Treaty set a boundary formalizing U.S. and British land claims. Unfortunately, ambiguity in the wording of the treaty left it unclear who exactly owned San Juan Island. Both sides claimed sovereignty, and Hudson’s Bay built a large sheep ranch here, while 25 or so Americans also settled in to farming the opposite side of the island.

This uneasy peace was soon to be disturbed by a pig in Her Majesty’s service. The pig, which belonged to the Hudson’s Bay Company, was fond of straying into American settler Lyman Cutlar’s farm and sampling his crops. Numerous petitions to the company brought no solution, and in June of 1859, a frustrated Cutlar shot and killed the pig. This outrage led to both sides pleading for military intervention; in short order, both sides got their wish. An armed standoff ensued, although few probably imagined that this drizzly cold war would ultimately last 12 years. British Royal Marines established a base at English Camp on the northern shore of the island, while the Americans fortified the southern tip, known as American Camp. Each force’s orders were the same: Return fire if fired upon, but do not initiate attack.

Tensions waxed and waned as Americans were distracted by the Civil War and troubles elsewhere. During this time, it’s said that both sides enjoyed fairly cordial relations, visiting each other’s camps and playing against one another in sporting events. If any other livestock got out of line during this period, it went unrecorded. Finally in 1872, the dispute was submitted for arbitration to Germany’s Kaiser Wilhelm I, who ruled in favor of the Americans. The British withdrew soon afterward, pigs and all, just barely having prevented what might have been one of the silliest wars in history.

The small, privately run Pig War Museum (Tucker and Guard Sts., 360/378-6495, 1–6 p.m. Wed.–Sat. Memorial Day through Labor Day, $5 adults, $4 seniors, $3 students, free for kids under 5). The museum is a bit odd and the exhibits are clearly done on a budget.