A. Natural Regions

Ireland consists of a central limestone plain rimmed by low, often rugged mountain ranges along the coasts. Gaps in the rim permit the plain to extend to the coast in several regions, notably along the eastern coast to the north of Dublin. Most of the central plain lies 60 to 90 m (200 to 300 ft) above sea level. It includes numerous lakes and large areas of marsh and peat bog, as well as some fertile agricultural land. Scattered ridges rise above the plain, but none reach any great height.

Among the principal mountain ranges are the Wicklow Mountains in the east, just south of Dublin, rising to more than 915 m (3,000 ft) above sea level. A number of smaller ranges, which have numerous local names, extend across the country. They include the Derryveagh Mountains and Blue Stack Mountains of Donegal in the northwest; the Maumturk Mountains and Nephin Beg Range, the latter containing Mount Nephin 719 m (2,359 ft), in the west; the Caha Mountains in the southwest, containing Mount Knockboy (707 m/2,321 ft); and the Boggeragh, Galty, and Knockmealdown mountains in the south. In the far southwest, in a range known as Macgillicuddy�s Reeks, stands Carrantuohill, which rises to 1,041 m/3,415 ft, the highest point in Ireland.

Ireland is a country of many rivers and lakes, known as loughs. The principal rivers of Ireland are the Erne and the Shannon, the longest river in the British Isles. The Shannon begins in the northwest and flows southwest before reaching the Atlantic Ocean through a wide, lengthy estuary. The Shannon, like the Erne, actually consists of a chain of lakes joined by stretches of river; half the length of the Shannon is made up of Loughs Allen, Ree, and Derg. Many of Ireland�s rivers, including the Liffey and Boyne in the east and the Lee in the southwest, are relatively short, draining mountains and hills near the sea. The southeastern part of the island is drained by a river system made up of the Suir, Nore, and Barrow and their tributaries.

Apart from the Shannon, which is navigable for most of its length, inland navigation largely depends on the remnants of a canal system built in the 18th and 19th centuries. Parts of this system have been restored, including the Royal and Grand canals that link Dublin to the Shannon. The completely rebuilt Ballinamore-Ballyconnell Canal, which originally opened in 1860, connects the Shannon and Erne.

Major loughs include Ree and Derg on the Shannon and Mask, Corrib, and Conn in the west. In the mountains of the southwest are the three small and picturesque Lakes of Killarney.

The eastern coast of Ireland is fairly regular with few deep indentations; the only sizable inlets are Dundalk Bay and Dublin Bay. In the south the largest harbor is Cork Harbour. Most of the western coast is extremely rugged and marked by drowned, or submerged, valleys and steep cliffs. Major inlets on the western coast include Bantry and Dingle bays in the south, Galway Bay in the center, and Donegal Bay in the north. Hundreds of small islands are scattered along the western coast. Among the largest are Achill Island and the Aran Islands.