San Juan Island National Historical Park, which is also called the American and English Camps in San Juan Island, is a United States National Park in Washington. The location consists of the different British and American Army campsites during the Pig War. Both camps were put up in 1859 in response to border conflicts brought about by a pig killing.

For 12 years, the camps were occupied and were only vacated until the Treaty of Washington signing. The British first left their camp in November 1872 and the Americans later on abandoned theirs in July 1874.

In 1961, the site was declared as a National Historic Landmark. Four years later, it was included in the National Register of Historic Places.

Basically, the park is still divided into 2 parts, the English Camp used by the British Royal Marines and the American Camp occupied by the US soldiers. The English camp is the only area in any US National Park that displays the British Union Flag.

Today, it is embedded on an island where recreational activities are being offered to visitors.