Facts about Physical Landscape

With many - but certainly not all - of the highlands and uplands close to the coast, it is easy to see how Ireland can be compared - in a very generalised way - to a saucer or, perhaps more accurately, to a pie crust that is high at the edges but sunk, rather irregularly, near the middle. This analogy is all the more striking when it is appreciated, as the geographers Gordon Herries Davies and Nicholas Stephens have shown, that not one of the 45 peaks which exceed 750 metres lies more than 56km (35 miles) from salt water.

The highest point above mean sea level is Carrauntoohil in the Macgillycuddy Reeks of County Kerry (1038 metres). Each of the other provinces has its own mountain zone. Lugnaquilla, Co. Wicklow, is the highest in Leinster (924 metres); Slieve Donard , Co. Down is the highest in Ulster (850 metres), and Mweelrea , Co. Mayo, the highest in Connacht (814 metres).

But a striking feature of Ireland is that, away from the northern and central parts of the midlands, its mountains are widely scattered and that many of them, like Galtymore, Co. Tipperary (919 metres) and the Slieve Bloom on the Laois-Offaly border, belong to small, relatively isolated groups. Some of the most famous, like Slievenamon , (Co. Tipperary, 719 metres), Croagh Patrick  and Nephin, (Co. Mayo, 763 and 806 metres), and Slieve Gullion (Co. Armagh, 575 metres) are just one mountain wide.

More extensive mountain groups are confined to a few districts. In the west, these include the highlands of Donegal, the Ox mountains of Sligo, the Twelve Bens of Connemara , and the mountains of the Kerry and Cork peninsulas (most notably those of Iveragh  and Dingle ). In the south, there are a series of smaller mountain groups that extend eastwards through the Boggeragh, Derrynasaggart and Knockmealdown  Mountains to the Comeragh mountains of west Waterford. In the east, the most extensive mountain groups are the Mourne and Carlingford  mountains of counties Down and Louth, and the Wicklow mountain group that reaches south-westwards to Mount Leinster and the Blackstairs mountains in Co. Wexford.

Plateaus characterise other upland areas, usually with altitudes between 150 and 400 metres. They are most notable in the north-east, where the steep-sided Antrim Plateau  dramatically overlooks the famous Antrim Coast Road, and glowers over the Giant's Causeway  on the north coast. This plateau originated in the lava flows that produced here basalt rock in a great period of volcanic activity over fifty million years ago.


Elsewhere, plateaus are associated with areas where grit and shale rocks from the much older 'Upper Carboniferous' geological period overlie the more widespread limestones. Such plateaus occur in parts of the south-east (Castlecomer,  Co. Kilkenny, Slieveardagh, Co. Tipperary), in west Co. Clare and across extensive areas of west Limerick, north Kerry and north Cork. Other plateaus capped by hard limestones occur in the north-west (Sligo-Leitrim), where the great flat-topped, steep-sloped Ben Bulben  (526 metres) is a particularly prominent feature.
 

However, most of the landmass, particularly towards the centre, is low-lying. Less than 5 % of the island lies above 500 metres, and well over 80% is below 200 metres. In many parts of the country, therefore, relief is quite subdued. It can nonetheless be quite varied - for example there is a major contrast between the hummocky low hills that make up the drumlin country of south Ulster and the near-level, plain-like conditions that prevail in some parts of the midlands such as mid-Tipperary, west of Dublin, and in east Galway.