The Cascade River is a river of the South Island of New Zealand. It flows north for 30 kilometres (19 mi) from its source in Mount Aspiring National Park in the Southern Alps, forming a deep valley between the Olivine Range and Red Hills Range. From the end of this valley it turns west to cross a low-lying swampy floodplain before entering the Tasman Sea close to Cascade Point, a headland halfway between Big Bay and Jackson Bay.