Dunmanus Harbour is situated on the southwest coast of Ireland about halfway up and on the southern shore of Dunmanus Bay. It provides an anchorage overlooked by a historic castle in a remote location with a pier for convenient landings.

The small rocky inlet provides good protection in all but strong north-westerlies. Access is straightforward at any stage of the tide but daylight is required to locate and enter the cove that can be difficult to identify.

A good weather window would be required to visit any of Dunmanus Bay’s havens if a vessel is time-restricted. Especially the inner havens that are situated close to the head of the cul-de-sac. If the prevailing winds were to come on strong, though good shelter may be found, it would be difficult however to sail out of the bay.

Keyfacts for Dunmanus Harbour

Position and approaches

Haven position

51° 32.550' N, 009° 39.882' W

This is the position of the anchorage in Dunmanus Harbour

What are the initial fixes?

The following waypoints will set up a final approach:

(i) Dunmanus Bay initial fix

51° 30.700' N, 009° 51.200' W

This initial fix positions an Atlantic approach to Dunmanus Bay and is set midway between Sheep's Head and Mizen Head.

(ii) Dunmanus Harbour initial fix

51° 32.780' N, 009° 39.920' W

This is immediately outside the entrance and a quarter of a mile from the anchoring area. Keeping the castle on a bearing of 173°T from here will steer the vessel through the centre of the entrance and into the anchoring area.

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?

Dunmanus Harbour indents the southern shore of Dunmanus Bay about 8 miles from the entrance and 1 mile southward of Carbery Island. It is a small and deep rocky bight overlooked by the high and square ruin of a tower house standing on an elevated rock on its southern shore. It has a substantial and modern pier that is used by local fishermen to land upon but apart from this, it is a very rural area.




Dunmanus Harbour is the first haven on this shoreline that provides a good anchorage in about its middle with 4 - 5 metres of water. The small quay is actively used by local fishing vessels. It may be possible, by arrangement with the local boatmen, for a medium-size boat to take to the bottom against the eastern wall. This rocky harbour is subject to a heavy ground swell in winter rendering it dangerous for small craft.

How to get in?

Use Ireland’s coastal overview for Mizen Head to Loop Head for seaward approaches and the the run up the long and narrow Dunmanus Bay is covered in the Dunbeacon Harbour entry.




Entered between Three Castle Head and Sheep's Head to the northward, Dunmanus Bay presents a rugged cliff face for most of the passage to Dunmanus Harbour and although Carbery Island provides an excellent positioning mark for the harbour it is not readily evident on approach.




On closer approaches, the four-storey Dunmanus Castle, 36 metres high, will start to show over the low Dunmanus Point. With this offering the first conspicuous mark the harbour then opens to reveal itself as a vessel continues eastward.




Keeping Dunmanus Castle on a bearing of 173° T, as set up from the initial fix, will steer a vessel through the centre of the entrance and into the anchoring area. The entrance has numerous rocks close along its shores on either side of the entrance and is a little over 150 metres wide at its narrowest point. Within the entrance, rocks encroach over 100 metres most particularly from the eastern shoreline. Keeping in depths of more than 10 metres of water at the entrance and reducing to no less than 4 metres when the bay opens out, clears all dangers.




Anchor in the middle of the bay just outside local moorings according to draft and conditions.



Land in the southeast corner of the bay at the substantial pier sheltered behind Rinneen Island. It is approached by passing south around the island as a reef that dries to 3.2 metres connects to it from the north shore.




Dunmanus Pier has just enough water off its head for a boat at low tide, but at low springs it may be necessary to lift an engine and paddle the last short distance into the wall.




The pier is home to a handful of local fishing boats but it may be possible for a boat to come alongside for a short period at high water. A medium-sized vessel could dry out alongside its eastern wall subject to local advice and availability.



Dunmanus Strand situated in the eastern end of the harbour, beyond Rinneen Island, dries out.
Tenders may be taken up onto a hard gravel shore that joins a track about 100 metres east of the pier.

Why visit here?

Dunmanus Harbour, in Irish 'Dún Mánais' and first recorded as 'Doonmanus' in 1614, takes its name from the fortified area that overlooks the harbour from the south of the inlet. Technically, this name is not taken from the bay's signature tower house that can be seen today but one that existed on the site at an earlier time. This 'Dún Maghnuis' was the 'fort of chief Manus', which, being a Danish name, indicates that it referred to an earlier Viking stronghold that must have stood on the rocky platform.




The building seen today was of the many tower houses built along the coast by the O’Mahony family. The O’Mahonys were a native Irish clan with two main centres, one around Bandon and the other along the Mizen Peninsula between Roaringwater Bay and Dunmanus Bay. The O’Mahonys ruled the ancient Ivahagh (Mizen) Peninsula for over four centuries with a succession of twenty O’Mahony chieftains. Of the 56 castles built in County Cork by Gaelic chiefs, 14 were built by the O’Mahonys to hold back successive encroachments by the Normans and other neighbouring Irish clans.

Dunmanus Castle was one of these tower houses through which the clan maintained much of their lands and prospered well into the 15th-century. But the tower houses had minimal defensive features and were surrounded by more comfortable houses which suggested that this was a time of peace and prosperity. The impressive structures, all built on the coastline, served primarily as centres for the fishing industry. This was the industry that was the beating heart of the clan's vast wealth during their time here.




From the mid-fourteenth to the seventeenth centuries this area was extensively fished by continental fleets, mainly from Spain and England. These were vast fleets as Donal O’Sullivan noted in 1605 that at least 500 fishing boats came to his nearby ports on the Beara Peninsula every year. Few, if any, of the Irish lords engaged directly in this industrial-scale fishing off their coastline. They preferred instead to control and profit from it in the form of taxes. Part of the catch may have been processed aboard the vessels and transported directly back to their home countries, but fishing also generated considerable onshore processing activity, that necessitated working with the chieftains. Key amongst these was the provision of safe harbours, sites for salting and oil extraction, boat repairs, as well as the provision of food and drink for the boat’s crews and, doubtlessly, a certain measure of protection money. So the tower houses were located along the coast to exploit and control that valuable fishing resources.




Dunmanus Castle was built-in about 1430 by Donagh Móre O'Mahoney. Though called a castle it is technically a tower house in a strictly military sense even though it does retain many of the features of a 'true' castle, such as battlements and narrow slit windows. It remained occupied by the family without a break for almost two centuries until 1602.




The Disaster at Kinsale in 1601, the climax of the Nine Years' War - a campaign by Hugh O'Neill, Hugh Roe O'Donnell and other Irish lords against English rule, brought the chieftain period to an end. After the defeat, the Irish mostly submitted to Carew who was, during the Tudor conquest of Ireland, the President of Munster. O'Mahony Fionn continued to hold out garrisoning their two strongest tower houses of Dunmanus and at Leamcon Castle, on the opposite side of the isthmus. But holding out was futile at this point and both were taken, in 1602, by the Lord-President of Munster, on his return to Cork after the siege of Dunboy.



The O'Mahonys Dunmanus briefly recovered Dunmaus castle during the rising of 1642 and 'Fynine mac Thaddeus Gankagh O'Mahony' died there in 1643, leaving an heir. But it would be a last fleeting overreach after which the family was outlawed. Thereafter their lands were confiscated, including Dunmanus Castle and 1,594 acres of land, and it was granted to New English settlers. Dunmanus Castle remains relatively intact today, except for parapets and gables. The shallow inlet immediately to the south of the platform is now crossed by a road bridge.



Although the tower house is the most conspicuous historical mark it is by no means the only historical object overlooking the harbour area. Just to the south of the mouth of the river that flows into the harbour, there is a strange burial boulder located in a flat grassy pasture that floods on spring tides. The rectangular 2.4 metres high and flat-topped boulder rests above three support stones that fill with water. Known as the Dunmanus East Boulder Burial there is no historical record of this megalithic monument or who was buried there.




From a boating point of view, this is the first and very well sheltered harbour of Dunmanus Bay. It is safe to moor a vessel here for several days to explore the area situated in the divide between Dumanus and Roaringwater Bays. Apart from the modern pier and road access, there are no facilities at this harbour. It is a wild and bleak place where you are most likely to be on your own with nature. Those who are fond of mussels and other shellfish and prepared to do some exploration will find plenty to dine on here.

What facilities are available?

Water is available from nearby houses but no supplies are available locally. The road running along the south side of the harbour leads to Long Island Bay’s village of Toormore. It is situated about 3.5 km along the road from the harbour. Here restaurants and a pub plus basic provisions can be had.

With thanks to:

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