It lies in Rosario Strait just off the eastern shore of Decatur Island and west of the city of Anacortes.

The entire island comprises James Island Marine State Park of the Washington State Park System.

It has a land area of 113 acres (46 ha) with 12,335 feet (3,760 m) of saltwater shoreline.

The camping areas combine for a total of 13 campsites and are connected by a loop trail.

[5] The property was transferred from the federal government to the Washington State Parks and Recreation Commission in 1964.