Loch Sunart  is a sea loch, its source is in Glen Tarbert east of Strontian and is bound to the north by the Ardnamurchan Peninsula and to the south by the Morvern district. It is the longest sea loch in the Highlands measuring some 19 miles in length. The maximum depth of the loch is 124 metres east of Càrna near the entrance to Loch Teacuis. Other islands in the loch include Oronsay, seaward of Càrna, Risga, which lies between the two larger islands, and Eilean Mòr, which lies towards the landward end of the loch in line with Beinn Resipol.