The Acheron River is a river in the South Island of New Zealand, in Marlborough and flows into the Waiau Toa / Clarence River.

It flows southwest and then east for a total of 76 kilometres (47 mi), joining the Waiau Toa / Clarence at the southern end of the Inland Kaikōura mountains.

The Alma and Severn Rivers flow into the Acheron before it joins the Waiau Toa / Clarence.

"Place name detail: Acheron River".

This article about a river in the Marlborough Region is a stub.