The town is situated at the base of Craigmore (1271 ft. high) and on the Laggan, a head-water of the Forth. Since 1885, when the Duke of Montrose constructed a road over the eastern shoulder of Craigmore to join the older road at the entrance of the Trossachs pass, Aberfoyle has become the alternative route to the Trossachs and Loch Katrine; this road, known as the Duke's Road, was opened to the public in 1931 when the Forestry Commission acquired the land.
Loch Ard, about 2 m. W. of Aberfoyle, lies 105 ft. above the sea. It is 3 miles long (including the narrows at the east end) and 1 mile broad. Towards the west end is Eilean Gorm (the green isle), and near the north-western shore are the falls of Ledard. Two miles Northwest is Loch Chon, at 90 ft. above the sea, 1.25 miles long, and about half a mile broad. It drains by the Avon Dhu to Loch Ard, which is drained in turn by the Laggan.
The slate quarries on Craigmore which operated from the 1820s to the 1950s are now defunct; at its peak this was a major industry.