Overview
Dún na Long Castle (Irish: Dún na Long, “Fort of Ships”) sits on a narrow promontory on the eastern edge of Sherkin Island, just off the southwest coast of County Cork. The name alone tells you what this place was built for: watching the water. From its position overlooking the entrance to Baltimore Harbour, the castle kept a close eye on every vessel navigating the inner waters of Roaringwater Bay. Today, the upper levels have long since collapsed, leaving a quiet, grassy ruin where wild parsley, thrift, and coastal herbs grow thick among the stones. It’s a subtle, living trace of the garden plots that once sustained the castle’s inhabitants.
A Turbulent History
The castle’s story is tied directly to the wealth and warfare of the O’Driscoll clan. Built around 1460 by Fínghin (Florence) O’Driscoll, Dún na Long was one of several fortified tower houses the clan constructed across the bay to project power and secure revenue. Their wealth came from controlling local fisheries, levying dues on passing merchant ships, and importing fine wines from France and Spain.
That wine trade sparked one of the most colourful episodes in the castle’s history. In 1537, the O’Driscolls intercepted the Santa Maria de Soci, a Portuguese vessel carrying wine bound for Waterford. After tasting the cargo, they invited the merchants to dinner, seized the ship, and distributed 72 tuns of wine among their neighbours. The citizens of Waterford did not take this lightly. In March of that year, a retaliatory force landed on Sherkin Island and launched a five-day assault. Dún na Long and the nearby Franciscan Friary were badly damaged, and the attackers made off with the friary’s bell, chalices, and the O’Driscoll’s prized galley. Locals still refer to the episode as the Battle of the Wine Barrels.
The castle was partially rebuilt in the decades that followed, but its fortunes shifted with the tides of wider Irish history. During the Battle of Kinsale in 1601, Spanish troops garrisoned the site. After the Spanish defeat, the stronghold was handed over to English commander Captain Roger Harvey. By 1645, it surrendered to Cromwellian forces, and later passed to the Beecher family, who used it as a working farmstead until 1768. After that, the stones were gradually scavenged for local building projects, leaving the atmospheric shell you see today.
Architecture & Layout
Dún na Long follows the classic Irish tower house design, but its placement on a narrow headland forced some practical adaptations. Rather than the typical compact square courtyard, the bawn (defensive outer wall) is elongated, stretching along the length of the promontory. A small corner tower once stood at the landward end where the bawn met the seaward wall, and historical sketches indicate a cannon was mounted on the seaward face – an unusual feature for a medieval Irish castle, underscoring how vital this lookout point was.
The original entrance was a raised entry located in the west wall, a common defensive feature that forced attackers to climb a ladder while defenders rained down fire. The ground-level doorway you can walk through today is actually a later enlargement of a former window opening. Inside, the walls show a pronounced base batter (they slope outward at the bottom), a deliberate engineering choice to resist battering rams and cannon fire. A picnic table now sits near the ruins, offering a quiet spot to look out across the harbour and imagine the fleet of ships that once slipped past under the castle’s watch.
Getting There & Practical Tips
Reaching Dún na Long is straightforward. The site is just a short, well-marked walk from the Sherkin Island ferry terminal at Harboursmouth. Once on the island, you can easily combine a visit to the castle with a walk to the nearby Franciscan Friary, which stands just a short stroll away. The two sites were originally built to complement each other: the castle provided military protection for the friary, while the friary offered spiritual services to the castle’s garrison.
- Ferry access: Services run year-round from Baltimore, taking around 10 to 15 minutes across the water. Check seasonal timetables in advance, as winter schedules can be reduced.
- Walking: The site is a 5–10 minute walk from the ferry terminal. The path is well-marked but can be damp or uneven in places.
- Costs & access: Free entry, open 24/7. No formal facilities on site, but toilets and refreshments are available at the ferry terminal and the Jolly Roger pub.
- Marina access: The nearby Seahorse Marina (often called Dún-na-Long Marina) operates mid-April to mid-September, offering mooring, electricity, and water for visiting vessels.
Best Time to Visit
The castle is accessible year-round, but the experience changes with the seasons. Spring and summer bring the island’s wildflowers into bloom, and the surrounding waters become active with seals, porpoises, and occasional dolphin pods. If you visit in late July or early August, you’ll likely catch the Sherkin Regatta, the island’s biggest annual event. Rowing crews, music, and food stalls fill the harbour, and the castle’s promontory becomes a lively vantage point for watching the boats.
For a quieter visit, aim for the shoulder months of May or September. The ferry schedules are reliable, the crowds are thin, and the light across Roaringwater Bay tends to be soft and clear. Bring a windbreaker and sturdy shoes – the coastal path can be damp and the Atlantic breeze is constant, but the views over the shipping lanes that once made this place wealthy are well worth the walk.