Inis Mor is the largest of the three, comprising about 7,600 acres. Here, you can find several ancient stone forts and churches, one of the most impressive of which is Dun Aengus. This semicircular fort rests on the edge of a cliff and consists of an inner court surrounded by a wall 20 feet high and 16 feet thick at the base.
There are about 1,100 inhabitants on Inis Mor, making it by far the most populated of the three islands. The main village and also main harbor is Kilronan.
The middle island, Inis Meain, is said to be the most untouched of the islands. Here you can experience the natural, cultural and traditional way of life of the islanders. Inis Meain has about 200 inhabitants, 300 flowering plants, as well as a wide variety of nesting birds. Here, too, you will find ancient stone forts, one of the oldest of which is Dun Fearbha from the 4th century AD. It is an unusual structure as it is more square than circular like the rest of the forts on the islands.
Inis Oirr, the east island, is also the smallest of the three with only 1,400 acres and 300 inhabitants. There is a large three-story castle dating back to around 1585, as well as several ruins of churches to be discovered here.
