River in New Zealand
The Allen River is a river in the West Coast district of the South Island of New Zealand. It drains the south side of the Allen Range, elevations to , which forms part of the boundary between West Coast and Tasman districts. The river has left and right branches for half its length, and the right branch has a major tributary stream in a valley between the two branches. The united river flows south through a narrow gorge and is joined by the Johnson River upstream of its confluence with the North branch of the Mōkihinui River.