The valley of the River Glengarriff, to the northwest of Glengarriff, was once the private estate of the Earl of Bantry. As such its ancient oak woodland has survived, the thick tree cover maintaining humid conditions, which allow ferns and mosses to flourish. The reserve is rich in wildlife – look out for red squirrels and siskins in the woods, otters and kingfishers along the river. Waymarked walking trails radiate from the main car park 1km north of the village.
There are five trails of varying lengths, from 500m to 3km, covering woodland, mountain, river and meadow. The purple-waymarked Glengarriff Wood Loop combines the best of all five in one route (8km, allow three hours).