Tolhuin is a town in the province of Tierra del Fuego, Argentina. It has 1,382 inhabitants as per the . It is located on the eastern shore of Lake Fagnano, in the southern part of the Isla Grande de Tierra del Fuego. It is the third largest settlement on the Argentine side of Tierra del Fuego after Ushuaia and Río Grande.
Tolhuin was founded on October 9, 1972. The word means "like a heart" in Selk'nam language. It lies on National Route 3, and is the only town between the cities of Ushuaia (about 103 kilometres to the south) and Río Grande (about 133 kilometres to the north) on this motorway.