Jackson Isle is a tiny islet close to High Island. It is home to some sheep farms that maintain a ferry link with Waterford. The islet is partly surrounded by blunt cliffs that pose minimal threat to sea transport, but did cause two shipwrecks in the early twentieth century giving them the name Cliffs of Hell.
Jackson Isle is home to three protected species of flower that grow in some parts of the High Island Forest too, but are most prominent on the islet itself. There are also remnants of Indian civilization in the form of arrowheads and allegedly a rock inscription showing a horse, although the authencity of this drawing is disputed.