The Arnaud River (formerly known as the Payne River) is a river in Nunavik, Quebec, Canada, flowing from the low plateaux of the Ungava Peninsula through a series of glacial lakes to Ungava Bay. Its mean discharge is approximately 15 km³ per year, but the river flows only in the summer as it is frozen to several metres for the rest of the year. The total length of the river is about 377 kilometres, but there are several main channels in the upper reaches of the river, most of them unnamed and hardly sighted even by the native Inuit.