Sometimes described as the most fjord-like of the sea lochs of northwest Scotland, it is steep-sided, with Beinn Sgritheall to the north and Ladhar Bheinn rising from the southern shore. The sea floor has been shaped by glaciation into five progressively deeper basins with relatively shallow sills; combined with the narrow and sheltered aspect of the loch and the high local rainfall, these result in an unusually wide variation of salinity and sea habitats over the length of the loch.