Tomas Northug is a Norwegian cross-country skier. He was born in Mosvik, and is the middle brother of Petter Northug and Even Northug.

Mosvik is a former municipality in the old Nord-Trøndelag county in Norway. The municipality was part of the Innherred region. The 219.37-square-kilometre (84.70 sq mi) municipality existed from 1901 until its dissolution in 2012. The old municipality encompassed the southern part of what is now the municipality of Inderøy in Trøndelag county. The municipality was located along the western shore of the Trondheimsfjorden and on the southwestern end of the Beitstadfjorden.