Upon the north it is barred by Loch Eitive, on the south by Loch Awe, and on the east by the dreadful pass of Brandir, through which an arm of the latter lake opens, at about four miles from its eastern extremity, and discharges the river Awe into the former.
The pass is about three miles in length; its east side is bounded by the almost inaccessible steeps which form the base of the vast and rugged mountain of Cruachan.

The crags rise in some places almost perpendicularly from the water, and for their chief extent show no space nor level at their feet, but a rough and narrow edge of stony beach.
Upon the whole of these cliffs grows a thick and interwoven wood of all kinds of trees, both timber, dwarf, and coppice; no track existed through the wilderness, but a winding path, which sometimes crept along the precipitous height, and sometimes descended in a straight pass along the margin of the water.

Near the extremity of the defile, a narrow level opened between the water and the crag; but a great part of this, as well as of the preceding steeps, was formerly enveloped in a thicket, which showed little facility to the feet of any but the martens and wild cats.

Along the west side of the pass lies a wall of sheer and barren crags.

From behind they rise in rough, uneven, and heathy declivities, out of the wide muir before mentioned, between Loch Eitive and Loch Awe; but in front they terminate abruptly in the most frightful precipices, which form the whole side of the pass, and descend at one fall into the water which fills its trough.