The portion of the river within Finland, the Näätämö, is approximately 50-kilometre (31 mi) long and drops down approximately 130 metres (430 ft) from the elevation of Lake Iijärvi (193 metres or 633 feet above sea level). At several points, the river widens into lakes, of which the largest are Lakes Kaarttilompolo, Vuodasluobal, and Opukas.
Based on annual catch, the Neiden is Norway's third most productive river for salmon fishing. Atlantic salmon, lake trout, sea trout, graylings and pike are all indigenous species.