Grenland is a traditional district in Telemark county, in the south-east of Norway. "Grenland" has referred to varying locations throughout history. In modern times, Grenland refers to the areas of the municipalities of Skien, Porsgrunn, Bamble, and Siljan. Sometimes the municipalities Kragerø and Drangedal are also considered to be part of the area. The region encompasses 1,794 square kilometres (693 sq mi) and has 122,978 inhabitants (2004), which translates as 12% of the area and 64% of the population of Telemark.
Grenland is the core area of a slightly larger traditional district known as Nedre Telemark ("Lower Telemark") which includes all of Grenland plus Midt-Telemark Municipality and the Heddal area of Notodden Municipality.