The Isle of Arran (Scots Gaelic: Eilean Arainn) is the largest island in the Firth of Clyde, Scotland, with an area of 430 km² (167 square miles). It is in the unitary council area of North Ayrshire. In the 2001 census it had a resident population of 5,058

.A granite island of western Scotland in the Firth of Clyde. It is a resort area noted for its scenery and its hunting and fishing.

The island lies in the Firth of Clyde between Ayr and Kintyre. The main village on the island is Brodick (Old Norse: broad bay) to which the main ferry to the mainland connects. Brodick Castle is a seat of the Dukes of Hamilton. Arran has many mountains in the north. The highest of these is Goat Fell at 874 metres (2,867 feet). The north of the island has many raised beaches and tall sea cliffs. The island is sometimes referred to as "Scotland in miniature", as it is divided into "Highland" and "Lowland" areas by the Highland Boundary Fault which runs northeast to southwest across Scotland. The island is a popular destination for geologists, who come to see intrusive igneous landforms such as sills and dykes.