Sørli is a former municipality in the old Nord-Trøndelag county in Norway. The 1,435-square-kilometre (554 sq mi) municipality existed from 1915 until its dissolution in 1964. The municipality encompassed the southern part of what is now the municipality of Lierne in Trøndelag county. The administrative centre of the municipality was the village of Mebygda.

Lierne is a municipality in Trøndelag county, Norway. It is part of the Namdalen region, and it is the largest municipality by area in Trøndelag. The administrative centre of the municipality is the village of Sandvika. Other villages include Inderdal, Mebygda, and Tunnsjø senter. The municipality borders Sweden to the south and east. Most of Lierne lies on the Swedish side of the drainage divide between Norway and Sweden.