ArendalArendal est une ville portuaire norvégienne située dans le comté d’Agder et la région du Sørlandet. Elle comptait au 2017, pour une superficie de . Elle est le centre administratif du comté. Arendal est sur la côte sud-ouest de la Norvège, au long du Skagerrak à l'est de Kristiansand. Les mines de fer d'Arendal ont été très célèbres au et réputés pour produire une belle fonte blanche ou acier. Le minerai de fer était qualifié de fer magnétique terreux, il était de couleur noire bleuâtre, éclatante ou mate, de densité avoisinant 2,2, opaque et tendre.
TromøyTromøy (historic: Tromø) is a former municipality in the old Aust-Agder county in Norway. The municipality existed from 1878 until its dissolution in 1992. The municipal area is now part of the municipality of Arendal in Agder county. The administrative centre was the village of Brekka, where the historic Tromøy Church is located. The municipality encompassed all of the island of Tromøya as well as many smaller surrounding islands such as Merdø, Gjesøya, Skilsøy, and Tromlingene.
HisøyHisøy (historically: Hisø) is a former municipality in the old Aust-Agder county in Norway. The municipality existed from 1881 until 1992 when it was merged into the municipality of Arendal in what is now Agder county. At the time of its dissolution, it was the smallest municipality in the whole county. The municipality encompassed the islands of Hisøya, Gjervoldsøy, Havsøya, Ærøya, Store Torungen, Lille Torungen, and several other small, unpopulated islands. The administrative centre was the village of Kolbjørnsvik on Hisøya island.
ØyestadØyestad is a former municipality in the old Aust-Agder county in Norway. The municipality existed from 1838 until 1992 when it was merged into the present-day municipality of Arendal which is now located in Agder county. At the time of its dissolution, the municipality of Øyestad encompassed most of the coastline between the towns of Grimstad and Arendal, along with the forested areas along the Nidelva river heading inland. Back in 1838, however, the municipality was far larger in size.