The 535-sq-km Shannon National Park is on the South Western Hwy, 53km south of Manjimup. Until 1968 Shannon was the site of Western Australia's biggest timber mill. Areas of this park were badly damaged by forest fires in 2015, but the forest is returning with new life. Check with the Department of Parks & Wildlife on the current situation especially during fire season.
The 48km Great Forest Trees Drive is a one-way loop, split by the highway. Start at the park day-use area on the north of the highway. From here there's an easy 3.5km walk to the Shannon Dam and a steeper 5.5km loop to Mokare's Rock, with a boardwalk and great views.
Further along, the 8km (return) Great Forest Trees Walk crosses the Shannon River. Off the southern part of the drive, boardwalks look over stands of giant karri at Snake Gully and Big Tree Grove.
In the park's southwest, a 6km (return) walking track links Boorara Tree with a lookout point over Lane Poole Falls.
