The Islands of the Firth of Clyde are the fifth largest of the major Scottish island groups after the Inner and Outer Hebrides, Orkney and Shetland. They are situated in the Firth of Clyde between Ayrshire and Argyll and Bute. There are about forty islands and skerries. Only four are inhabited, and only nine are larger than 40 hectares (99 acres). The largest and most populous are Arran and Bute. They are served by dedicated ferry routes, as are Great Cumbrae and Holy Island. Unlike the isles in the four larger Scottish archipelagos, none of the isles in this group are connected to one another or to the mainland by bridges.