The Lerderderg River diversion tunnel, known as The Tunnel, is located on the Lerderderg River approximately 25 km north-west of Bacchus Marsh, Victoria, Australia. The river flows around a spur in a horseshoe bend. The tunnel was driven through the spur diverting the river and allowing the exposed river bed to be sluiced for alluvial gold.[1]
The tunnel was dug during the Victorian gold rush, most likely between 1855 and 1870, and is one of around thirteen river diversions surviving from that era.[2]
The site is within the Lerderderg State Park. It is a 3.0 km walk along Byers Track upstream from the O'Briens Crossing Picnic Area.[1][3]