Gratangen or Rivtták is a municipality in Troms county, Norway. It is part of the traditional region of Central Hålogaland. The administrative centr…Gratangen or Rivtták is a municipality in Troms county, Norway. It is part of the traditional region of Central Hålogaland. The administrative centre of the municipality is the village of Årstein. The 313-square-kilometre municipality is the 261st largest by area out of the 357 municipalities in Norway. Gratangen is the 331st most populous municipality in Norway with a population of 1,070. The municipality's population density is 3.4 inhabitants per square kilometre and its population has decreased by 5.7% over the previous 10-year period.