Årnset or Rissa is the administrative centre of Indre Fosen Municipality in Trøndelag county, Norway. It is located on the north shore of the lake Botn about 10 km south of the village of Hasselvika and about 12 km north of the villages of Stadsbygd and Askjem. The 0.87 km2 village has a population (2024) of 1,250 and a population density of 1437 PD/km2. Rissa Church, Rein Church, and Rein Abbey are all located in and around Årnset. Prior to 2020, the village was the administrative centre of the old Rissa Municipality (which is why the village is known as Rissa). On 1 January 2020, Rissa Municipality became part of Indre Fosen Municipality, and the village became the administrative centre of the new municipality.