Trentham Falls is the longest single drop waterfall in Victoria, plunging some 32 metres over basalt columns. Trentham Falls was formed some five million years ago from molten lava rapidly cooling as it flowed along the old Coliban River valley. At the base of the Falls, quartz gravel and the former river bed can be seen. The Falls reserve protects one of the best remnants of original vegetation in the area, with stands of manna gum, messmate, stringybark and narrow-leaved peppermint. The reserve is ideal for picnics or barbecues, with picnic tables, fireplaces and toilets provided for visitors. The Trentham Cascades are a short walk further north from the Falls Reserve car par