Hessdalen is a 15 km long valley in Norway, located approximately 120 kilometres south of Trondheim city and approximately 35 km north of Røros mining town. (Trondhjem is a city and municipality in the county of Sør-Trøndelag, Norway. is a Town and municipality in the county of Sør-Trøndelag, Norway. It is a part of Holtålen municipality in Sør-Trøndelag county. Holtålen is a municipality in the county of Sør-Trøndelag, Norway is a county in the area Trøndelag in Norway, bordering Nord-Trøndelag, Møre og Romsdal, Oppland and Hedmark.
In the area of Hessdalen occur sometimes ominous luminous phenomena (Hessdalen lights). Hessdalen Lights are unexplained lights (a type of Will-o'-the-wisp) usually seen in the valley of Hessdalen, Norway.
The first element is the rivername Hesja - the last element is the finite form of dal m 'dale, valley'.