Årnset (also known as Rissa) is the administrative centre of the municipality of Indre Fosen in Trøndelag county, Norway. It is located on the north shore of the lake Botn about 10 kilometres (6.2 mi) south of the village of Hasselvika and about 12 kilometres (7.5 mi) north of the villages of Stadsbygd and Askjem.

Rissa Church, Rein Church, and Rein Abbey are all located in and around Årnset.

The 0.9-square-kilometre (220-acre) village has a population (2018) of 1,195 and a population density of 1,328 inhabitants per square kilometre (3,440/sq mi).