Skien (Norwegian: [ˈʂêːən] ) is a municipality in Telemark county, Norway. It is located in the traditional district of Grenland, although historically it belonged to Grenmar/Skiensfjorden, while Grenland referred the Norsjø area and Bø. The administrative centre of the municipality is the city of Skien, which is also the administrative centre of the whole county. Some of the notable villages in the municipality include Åfoss, Hoppestad, Klovholt, Luksefjell, Melum, Kilebygda, Skotfoss, Sneltvedt, and Valebø.
The 779-square-kilometre (301 sq mi) municipality is the 147th largest by area out of the 356 municipalities in Norway. Skien is the 18th most populous municipality in Norway with a population of 56 866. The municipality's population density is 77.8 inhabitants per square kilometre (202/sq mi) and its population has increased by 5.5% over the previous 10-year period. The conurbation of Porsgrunn/Skien is reckoned by Statistics Norway to be the seventh largest urban area in Norway, straddling an area of three municipalities: Skien municipality (about 62% of the population), Porsgrunn Municipality (30%), and Bamble Municipality (8%). This entire area is home to more than 100,000 people.