Ireland, an 84,421 km² island in the North Atlantic, features low coastal mountains ringing flat midlands, with only 3 peaks over 1,000 m and 457 above 500 m. MacGillycuddy's Reeks host Carrauntoohil at 1,039 m—the highest. Other ranges: Wicklow Mountains, Mourne Mountains, and inland Galtee Mountains. Geological history spans 1.7 billion years: ancient volcanism, tropical seas, Caledonian orogeny uniting terrains ~440 million years ago, and Quaternary glaciations sculpting U-shaped valleys and karst limestone plateaus. The Shannon River (360 km longest) drains from these uplands, while Lough Neagh (392 km² largest lake) reflects glacial origins, fostering bogs and heather moors in protected landscapes.
