Offshore Lighthouses are lighthouses that are not close to land. There can be a number of reasons for these lighthouses to be built. There can be a shoal, reef or submerged island several miles from land.
The current Cordouan Lighthouse was completed in 1611 seven kilometers from the shore on a small islet, but was built on a previous lighthouse that can be traced back to 880 and is the oldest surviving lighthouse in France. It is connected to the mainland by a causeway.
The Stratford Shoals, Middle Ground lighthouse in Long Island Sound is about 6 miles from land. There are many examples of such lighthouses throughout the world. Many are considered to be stag lighthouses.
Most caisson lighthouses are offshore lighthouses.