Loch Sween is a sea loch located near Lochgilphead, Argyll and Bute, Scotland. Castle Sween is located on the southern shore towards the seaward end of the loch. The village of Tayvallich, a favoured haven for water craft as it sits at the head of sheltered Loch a' Bhealaich, lies on the northern shore.The shape of the loch, which is oriented from south west to north east, is complex. The inner, eastern end has several inlets.