Arendal (Urban East Norwegian pronunciation: [ˈɑ̂ːɳɖɑːɫ] ) is a municipality in Agder county in southeastern Norway. Arendal belongs to the region of Sørlandet. The administrative centre of the municipality is the city of Arendal (which is also the seat of Agder county). Some of the notable villages in Arendal include Rykene, Eydehavn, Færvik, Strengereid, Kongshavn, Kilsund, Brattekleiv, Torsbudalen, Longum, Saltrød, Staubø, Vrengen, and Kolbjørnsvik. The offices of UNEP/GRID-Arendal are also located in the city of Arendal.
The 270-square-kilometre (100 sq mi) municipality is the 273rd largest by area out of the 356 municipalities in Norway. Arendal is the 24th most populous municipality in Norway with a population of 45,891. The municipality's population density is 179.9 inhabitants per square kilometre (466/sq mi) and its population has increased by 5.9% over the previous 10-year period.