The Istra is a river in Rauma Municipality in Møre og Romsdal county, Norway. The river runs through the Isterdalen valley before emptying into the Rauma river in the Romsdalen valley. It discharges into the Rauma about 3 kilometres (1.9 mi) south of the town of Åndalsnes. The 17-kilometre (11 mi) long river Istra has a basin area of 66 square kilometres (25 sq mi).