O'Brien's Castle, Connacht Travel Guide

4.5 (30)

Explore the historic O'Brien's Castle on Inisheer: a medieval tower house offering stunning views and a glimpse into Ireland's past.

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O'Brien's Castle

Perched atop Inisheer, the smallest of the Aran Islands, O'Brien's Castle is a 15th-century tower house built by the O'Brien clan on the site of a much older ringfort. Over centuries, it has witnessed sieges, conquests, and eventual ruin, offering visitors a tangible link to Ireland's tumultuous past and panoramic views of the island and coast.

A brief summary to O'Brien's Castle

Oir, Inisheer, Inisheer, Co. Galway, IE

From Eve

Know before you go

Hi, I'm Eve. Here are a few practical things to know before exploring O'Brien's Castle.

Wear comfortable shoes, as the terrain around the castle is uneven and rocky.
Check the weather forecast before visiting, as it can be windy and exposed at the castle.
Bring a camera to capture the panoramic views of Inisheer and the surrounding coastline.

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Book tours with entry

Private cultural tour of Inisheer, Aran Islands with lunch, horse and trap tour

5.0

2 reviews

$973.51

Book tours without entry

Small Group - Cliffs Cruise and Aran Islands in a Day from Galway

4.9

438 reviews

$140.50

Getting There

Walking

From the Inisheer ferry pier, O'Brien's Castle is approximately a 15-minute walk. Follow the road leading away from the pier and beach. The castle is located on the highest point of the island and is visible from most locations. The route involves a gradual uphill walk. There are no admission fees or mandatory access costs.

Discover more about O'Brien's Castle

O'Brien's Castle, also known as Furmina Castle, stands as a proud, if crumbling, sentinel on Inisheer (Inis Oírr), the smallest of the Aran Islands. Built around 1400 by the Clann Teige, a branch of the powerful O'Brien family, the castle occupies the site of Dún Formna, an ancient ringfort dating back to between the 5th century BC and 1st century AD. The location was strategically chosen, offering commanding views of Galway Bay and the mainland.Throughout its history, O'Brien's Castle has been a focal point of conflict. In 1582, the O'Flahertys of Connemara, rivals of the O'Briens, seized the castle. Then, in 1652, during the Cromwellian conquest of Ireland, Oliver Cromwell's army captured and intentionally damaged the castle to prevent its future use as a stronghold.Today, O'Brien's Castle is a National Monument of Ireland. Though largely in ruins, its rectangular donjon (keep) still evokes a sense of its former grandeur. Visitors can explore the remains of the four-story structure, including the great hall on the first floor and the vaulted chambers in the basement. A notable feature is the corbel of a bartizan, which features a human face carved into it. From the castle's elevated position, one can appreciate the island's unique landscape, characterized by stone walls, fields, and other landmarks like Teampall Chaomháin and the Plassey shipwreck.