Skien is a town/city in Skien Municipality in Telemark county, Norway. It is the administrative centre of the municipality. The town is located along the Skienselva river, about 8 kilometres (5.0 mi) to the northwest of the town of Porsgrunn. The villages of Skotfoss, Åfoss, and Klovholt are located about 5 kilometres (3.1 mi) to the west of the town, the village of Sneltvedt lies about 2 kilometres (1.2 mi) to the east of the town, and the village of Hoppestad lies about 6 kilometres (3.7 mi) to the northwest.
Skien and Porsgrunn are considered to be a conurbation and grouped together as part of the Porsgrunn/Skien metropolitan area. Because of this, the population and area data for this town has not been separately tracked by Statistics Norway. What is tracked, is the portion of the metropolitan area located in Skien Municipality. In 2022, the urban area of Skien measured 26.24 square kilometres (6,480 acres) it had a population of 50,142 with a population density of 1,882 inhabitants per square kilometre (4,870/sq mi).