The Trossachs glen lies between Ben A'an to the north and Ben Venue to the south, with Loch Katrine to the west and Loch Achray to the east. It lies at the centre of the wider region, which is generally regarded as being bounded by Glen Gyle to the south, with the western boundary being the road between Stronachlachar and Aberfoyle. Loch Doine, Loch Voil, and Loch Lubnaig form the northern and eastern boundary of the area. The A821 road between Aberfoyle and Callander runs through this glen, and is the main access route into the Trossachs from the south and east. The section between Aberfoyle and the Trossachs glen runs through the Achray Forest, reaching a height of 238 m above sea level at the summit of the Duke's Pass. The main route to Callander continues east via the north shores of Loch Achray and Loch Venachar, whilst a branch of the A821 heads west to finish at the western end of Loch Katrine. No public road continues along the shore of Loch Katrine, although the Great Trossachs Path allows walkers and cyclists to follow the northern shore round to Stronachlachar on the western shore. From here a minor road heads west to Loch Lomond. Stronachlachar can also be reached by the B829 road from Aberfoyle, which passes north of Loch Choin and Loch Ard.