Start at the memorial stone at the Katrine Waterworks (OS grid ref 421091). Circumnavigate every river and stream that flows into Loch Katrine, Loch Arklet and Loch Finglas (Glasgow’s water supply). Finish back where you started. 

Terrain type: 80% unmarked open hillside, with occasional sheep and deer trods. Steep gradients in many places. Very uneven and boggy ground in places. There is a 10km section of hard gravel path between Brig O''Turk and Ben Venue beallach.

This route has historically been for decades both a training run and a "rite of passage" for runners in the Lynchburg, Virginia area. Some of the notable runners include David Horton (former holder of Appalachian Trail FKT,  Pacific Crest Trail FKT, 2x winner of Hardrock 100, and much more!).