The Seattle Times reported that the property sold on Dec. 20.
Allan Island, named after a Navy hero, is southwest of Anacortes. Data from the Northwest Multiple Listing Service shows it was listed in 2005 for $25 million and slashed to $13.5 million in 2009.
The Windermere real estate agent who listed the property, Wallace Gudgell, didn't immediately return the newspaper's requests for comment on Monday.
Allen bought the island in 1992 to build a vacation home. It's only accessible by private plane, boat or float plane.
More Northwest Headlines
State says firefighting resources stretched thin 1:19 p.m. Longtime environmental activist Wendell Wood dies hiking Benton County man dies from West Nile virus 1:13 p.m. Man fatally shot outside Seattle restaurant 1:13 p.m. Justices: Defendantís youth can be basis of lighter sentence Dozens under evacuation orders near Baker County wildfires Judge bars release of licensing information on strippers Federal audit says BPA wasted $5.2 million on nixed software
Our new comment system is not supported in IE 7. Please upgrade your browser here.