Innerdalen is a valley in Sunndal Municipality in Møre og Romsdal county, Norway. In 1967, the valley was established as Norway's first nature reserve. The valley and nature reserve begins at the village of Ålvundeid by the Norwegian National Road 70 in the west and stretches approximately 25 kilometres (16 mi) to the east to Innerdalsporten. It lies within the Trollheimen mountain range.The valley is regularly visited by mountain climbers.