Castle Island is a small uninhabited island in Roaringwater Bay located on Ireland’s southwest coast at the head of Long Island Bay. The island offers anchorages off its northern and southern shores with the northern side, off of the island’s small pier, being the preferred option.

Set within an enclosed channel, and well sheltered between the mainland and Castle Island to the south, the anchorage offers good protection from all but very strong westerly or north-easterly winds. Approaches to the general area are straightforward with the western end approach being marked and lit.

Keyfacts for Castle Island (North Side)

Position and approaches

Haven position

51° 30.741' N, 009° 30.039' W

Just off the head of the pier

What is the initial fix?

This is 300 metres west of the Amelia Rock Marker and on the harbour’s 346° T in-line leading through the entrance. The anchoring area in Schull Harbour is a mile and a half from here.

What are the key points of the approach?

Not what you need?

To find locations with the specific attributes you need try:

What's the story here?

Castle Island is a small island in Roaringwater Bay just off the eastern side of the entrance to Schull Harbour. It is the highest of three low islands that adjoining the coast here, about a ½ mile offshore, and are separated from each other by narrow passes. They are set in a line and, from west to east, are Long Island, Castle Island and then Horse Island. Castle Island is the middle of the three and is often known as such. It is approximately 124 acres or 50 hectares, privately owned but uninhabited. It has a substantial pier and slipway beneath the ruins of its castle that offers well-sheltered access to the island in most weather conditions and at all tidal stages.




The anchorage is in Castle Island Channel which is well protected and deep shallowing steeply to the shore.

How to get in?

Offshore details are available in southwestern Ireland’s Coastal Overview for Cork Harbour to Mizen Head seaward approaches and Rossbrin Cove for general approach directions as the anchorage is 1 mile west by southwest of Rossbrin and immediately south of its approach path through Castle Island Channel.

Castle Island Channel is free from danger and has 16 metres in the entrance decreasing to 10 at its eastern end. The conspicuous Derreennatra manor house on the north shore, close to Trawnwaud, and the unmistakable old ruins of the castle plus the pier on Castle island make all readily evident.



Anchor according to draft off the old pier. Land on the beach alongside the pier on Castle Island or on the mainland side at Trawnwaud.

Why visit here?

Castle Island, or in Irish Meadhon Inis meaning Middle Island, takes its name from the island’s 14th century Castleduff castle that belonged to the O'Mahoney clan - see Rossbrin Cove .




The name Castleduff is derived from Caislen Dubh meaning 'black or dark castle' the ruin of which may be seen today above the quay. The building stands in an open position on a promontory that, except for the south, is surrounded by low cliffs. The site perfectly commands the narrow neck between the two halves of the hour-glass-shaped island whilst also offering superb views of Roaring Water Bay, Cape Clear Island and the Atlantic beyond. It would have also been sited to make the best of the landing area beneath. Although the pier is modern, the beach that it is laid upon is the best natural landing point on the island today as it was in medieval times.

An 1842 Ordinance Survey indicates that this was the main nucleus of the three settlements on the island. At that time, according to the 1837 census, the island was home to 89 people. It is believed a small community of approximately fifteen families were resident on the Island up to the year 1870. Their main occupations were farming and fishing, particularly fishing for lobsters. But the small scraps of wind-swept lands were not owned by the islanders but rather the Townsend family who used a land agent called the Marmions to manage their interests. Cleary the Marmions had difficulty collecting rents from the islanders as in 1890 the population was vastly reduced by way of eviction.




The Cork County Eagle, March 7th, 1890 observed events. . . A few days ago, the sheriff’s officer from Skibbereen made his appearance in Schull, surrounded by a force of police, on an evicting expedition. After a short delay, they proceeded to the water’s edge where their galleys were found to await them and the sheriff’s representative having secured himself in one of the crafts, the whole party proceeded to sea for a distance of some three miles when they landed on Castle island. This wild and sea-washed home of a few small farmers and fishermen is the property of Mr Thomas Henry Marmion . . . whose interest in recent years appears more of an incumberance or embarrassment than any advantage as the poor creatures who live in it (misnamed farmers) and on the many islands surrounding it, have to live chiefly on the profits of the sea. The fortification of Jerry Nugent was the first laid siege by the invading army, Jerry’s offence being that he owed a few years’ rent which he found impossible to pay and he was, therefore, sent adrift on the sea-washed rocks where he had a full view of the passing emigrant ships which will probably bear him away to seek out a livelihood in the land of the stranger.

During the early part of the 20th-century, it is believed the island retained a population of about 30 permanent residents as is evidenced by its sturdy stone quay. But in the latter half of the century, the population declined and it slowly became uninhabited.




Today the island is very easy to land on, at the beach by the pier beneath the castle. Being relatively small and with many old boreens that provide easy walking, it is an ideal place to come ashore and explore on foot. A trip around the island presents treeless expanses of hill and bog plus rocky cliffs surrounded by mixed shingles and two sand beaches on an otherwise rocky foreshore. The remains of the settlement dwellings may be seen close to the tower of the ruined castle, above the old pier, and there is also another group of abandoned houses at the extreme northeastern end of the island. Now the only life on the island is the sheep that graze in and around the deserted enclosures.

From a boating point of view, the anchorage just a mile outside the entrance to Shull Harbour provides an excellent quieter alternative to the busy boating centre and town. Although Castle Island has no facilities, the secluded and very scenic location makes for a worthwhile visit. There are excellent views to enjoy from many ideal locations whilst having a picnic. Likewise, there are extensive boating amenities as stone's throw away in Schull and Baltimore and also Rossbin. Whilst sailing around the islands, look out for dolphins, porpoises, seals, whales and even sharks.

What facilities are available?

There are no facilities at this remote island anchorage.

Any security concerns?

Never an issue known to have occurred to a vessel anchored of Castle Island.

With thanks to:

Burke Corbett, Gusserane, New Ross, Co. Wexford.