O'Brien's Castle, Medieval tower house in Inisheer, Ireland.
O'Brien's Castle is a rectangular stone tower standing at one of the highest points on Inisheer island, dating from around 1400. The structure features a first-floor entrance and vaulted chambers at ground level, typical of Irish tower houses from this period.
The O'Brien family built the castle around 1400 as a defensive stronghold, and the O'Flaherty clan took control in 1582. Cromwell's forces damaged it during their 1652 campaign, ending its role as an active military site.
The carved human face on a corbel stone inside reflects medieval Irish craftsmanship traditions. Such decorative details reveal how builders invested care in personalized touches even in defensive structures.
The location sits at a high point on Inisheer island and is easily reachable for visitors exploring the area. Inside, expect uneven ground and steep stairs, so plan accordingly for your time there.
The castle sits on the remains of an ancient ringfort called Dún Formna, occupied between the 5th century BC and the 1st century AD. This layering shows the site held importance for over a thousand years before the tower was built.
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