San Juan Island National Historical Park

San Juan Island National Historical Park, also known as American and English Camps, San Juan Island, is a U.S. National Historical Park owned and operated by the National Park Service on San Juan Island in the state of Washington. The park is made up of the sites of the British and U.S. Armies' camps during the Pig War. Both of these camps were set up in 1859 as response to a border dispute triggered by the killing of a pig. The camps were occupied for 12 years, until the Treaty of Washington was signed, negotiated by Kaiser Wilhelm I of Germany. The British abandoned their camp in November 1872, while the American camp was disbanded in July 1874.

The site was designated a National Historic Landmark in 1961, and listed on the National Register of Historic Places in 1966.

The park is divided into two parts; an American Camp where US soldiers were stationed, and a British Camp, where the British Royal Marines established a garrison. The British Camp is the only part of a US national park that commemorates a British military site and the only one that flies the British Union Flag.