Point No Point Light, located in the Chesapeake Bay off the eponymous point several miles north of the mouth of the Potomac River, was constructed as part of a program to add lighted navigational aids in a thirty mile stretch of the bay between Cove and Smith Points. - Wikipedia
Yes, for sale, or maybe not for sale:
Here is an extract from the Addendum:
Offshore lighthouse in Chesapeake Bay - disposal includes only the lighthouse. -PLEASE NOTE- The bidding has been temporarily suspended due to the fact that the Navy has notified GSA that the lighthouse serves as a boundary marker for the Navy's restricted area danger zone as defined in 33 CFR 334.200. For complete details, please read the Addendum #2, which can be downloaded from this page - US Government
1) Bidding is hereby temporarily suspended. The Department of Navy (Navy) has notified the General Services Administration (GSA) that the Point No Point Lighthouse serves as a boundary marker for the Navy’s restricted area danger zone as defined in 33 CFR 334.200 (see attached). Further, the Navy has informed GSA that it may require additional deed restrictions for the use of the lighthouse. Those will be made available to all registered bidders and posted on www.auctionrp.com as soon as they are made available to GSA.
So despite living on an 'island' you still are going to have a neighbor, and it sounds like a nagging one at that. Then again, you could be buying front-row tickets for... something.
H/t to Private Islands Blog where I saw this story first.