The Tunnel & Sardine Creek Hike (11.3km)

Rising in the Great Dividing Range, the Lerderderg River has cut a 300 metre deep gorge through sandstone and slate, almost bisecting the park. The park has a wide variety of vegetation and wildlife and some interesting relics of gold mining. Lerderderg State Park encompasses scenic and geological gorge formations surrounding the Lerderderg River as well as the volcanic cone of Mount Blackwood. The adjacent and separate block called the Pyrete Range forms part of the park. The Lerderderg is known for its remote setting and the 300m deep Lerderderg River gorge is a dominant feature. Private land abuts the park to the south and the Wombat State forest abuts to the north and west.

Lerderderg State Park (incorporating the former Pyrete State Forest) is a 14,250-hectare park located between Bacchus Marsh and Blackwood, an hour's drive from Melbourne, Australia. There are several maintained tracks for walking through the park and camping is allowed.

The park is named for the Lerderderg River which has cut the 300 metre deep Lerderderg Gorge through sandstone and slate, almost bisecting the park. Parks Victoria maintains six designated walks: three short walks of 3.5 km or less; Blackwood-O'Briens Crossing and return (22 km); O'Briens Crossing-Cowan Track loop (14 km); and the overnight walk O'Briens Crossing to Mackenzies Flat (20 km).

In addition, one leg of the Great Dividing Trail, the Lerderderg Track, passes through the park, entering from Blackwood in the park's northwest, and exiting south towards Bacchus Marsh. Bicycles are prohibited from one section of this track, due to a conservation area.