King Guaire was a local 'king' in the South Galway area in the 7^th century, although he is described as the 'King of Connacht', a far larger area. He was renowned for his generosity and hospitality and is said to have had one arm longer than the other from giving! He befriended St. Colman , the local saint, who founded the monastery at Kilmacdaugh. Guaire had a fort, or dún, at Gort, but his main dún was at Dunguaire ( the name means 'the fort of Guaire').

However nothing remains of this earlier structure, and the present tower was built early in the 16th century by the O'Hynes family. It is in use as a tourist attraction, offering a shop, guided tours, and banquets. The remains of an earlier fortification can be seen nearby. With water on three sides, it must have seemed an ideal location for a fortification.