Roaring Billy Falls, Cascade waterfall in Mount Aspiring National Park, New Zealand

Roaring Billy Falls is a cascade waterfall in New Zealand's Westland District featuring a vertical drop of approximately 30 meters. The water tumbles through thick native forest before flowing into the Haast River system below.

This waterfall landscape formed through geological processes during the uplifting of the Southern Alps millions of years ago. The stream has carved deeper into the rock face over extended periods, creating the current formation.

The walk to the viewing point crosses a fertile alluvial terrace beneath silver beech, southern rātā and kāmahi, with podocarps such as rimu, miro, mataī, kahikatea and Hall's tōtara. The understory holds māhoe, patē, mountain horopito, wineberry and tree fuchsia, while soft tree fern and wheki grow densely along the path.

From the car park on State Highway 6, a 1 km return gravel and boardwalk track leads through silver beech and podocarp forest to the gravel bed of the Haast River. The falls are viewed from across the river; there is no viewing platform and the track is not wheelchair accessible.

The walkway crosses a fertile alluvial terrace where silver beech, southern rātā and kāmahi form the canopy above a dense understory of tree ferns, mostly soft tree fern and wheki. Among the smaller ferns is Colenso's hard fern, also called waterfall fern, which grows beside the track.