Located off the coast of Washington. You take a ferry from the Anacortes Ferry Terminal, about 1.5 hours north of Seattle. But a ticket for you, your bike or your car. You can also rent a car or bike on the island if you don't have either. The park is a mostly flat 5.5 miles from the Friday Harbor to the visitor center.
The park preserves the history of the US / Canada border dispute that happened on the island. American and British troops were both encamped on the island and almost launched a war over the shooting of a Canadian pig who was rooting around in an American garden. Ultimately, the dispute was peacefully resolved by the International Boundary Commission. The islands are now part of the United States while Canada got the Southern Gulf Islands on the other side of the boundary line.