Rockall - Geography

Geography

The islet of Rockall makes up the eroded core of an extinct volcano (a volcanic plug), and is one of the few pinnacles of the surrounding Helen's Reef. It is located 301.3 km, or 162.7 nmi west of the island of Soay, St Kilda, Scotland, and 423.2 kilometres (263.0 mi), or 228.5 nmi, north-west of Tory Island, County Donegal, Ireland. The surrounding elevated seabed is called the Rockall Bank, lying directly south from an area known as the Rockall Plateau. It is separated from the Western Isles by the Rockall Trough, itself located within the Rockall Basin. (Also known as the "Hatton Rockall Basin".) The Anton Dohrn Seamount is a submarine elevation on Rockall Trough about halfway between Rockall and the Outer Hebrides.

Cold-water coral mounds have been identified in the region, They are currently being researched. Rockall lies near the Darwin Mounds, deep water coral mounds about 185 km (100 nmi or 115 mi) north-west of Cape Wrath. These corals are long-lived and slow-growing, a justification for designating Rockall and the Rockall as a Marine Protected Area.

Rockall is about 25.3 metres (83 ft) wide and 31 metres (102 ft) long at its base and rises sheer to a height of approximately 21.4 metres (70 ft). It is regularly washed over by large storm waves, particularly in winter. There is a small ledge of 3.5 by 1.3 metres (11 by 4 ft), known as Hall's Ledge, 4 metres (13 ft) from the summit on the rock's western face. It is the only named geographical location on the rock, other than Rockall as a whole.

The nearest point on land from Rockall is 301.3 km, or 162.7 nmi, east at the uninhabited Scottish island of Soay in the St. Kilda archipelago. The nearest inhabited area lies 303.2 km, or 163.7 nmi, east at Hirta, the largest island in the St. Kilda group, which is populated intermittently at a single military base. The nearest permanently inhabited settlement is 366.8 km, or 198.1 nmi, west of the headland of Aird an Runair, near the crofting township of Hogha Gearraidh on the island of North Uist at NF705711 (57°36′33″N 7°31′7″W / 57.60917°N 7.51861°W / 57.60917; -7.51861 (Hogha Gearraidh / Hougharry)). North Uist is part of the Na h-Eileanan Siar council area of Scotland.