Agder

Agder is a county () and traditional region in the southern part of Norway and is coextensive with the Southern Norway region. The county was established on 1 January 2020, when the old Vest-Agder and Aust-Agder counties were merged. Since the early 1900s, the term Sørlandet ("south country, south land, southland") has been commonly used for this region, sometimes with the inclusion of neighbouring Rogaland. Before that time, the area was considered a part of Western Norway.

The area was a medieval petty kingdom, and after Norway's unification became known as Egdafylki and later Agdesiden, a county within the kingdom of Norway. The name Agder was not used after 1662, when the area was split into smaller governmental units called Nedenæs, Råbyggelaget, Lister, and Mandal. The name was resurrected in 1919 when two counties of Norway that roughly corresponded to the old Agdesiden county were renamed Aust-Agder (East Agder) and Vest-Agder (West Agder). Even before the two counties joined in 2020, they cooperated in many ways; the University of Agder had sites in both Aust-Agder and Vest-Agder, as did many other institutions, such as the Diocese of Agder og Telemark, the Agder Court of Appeal, and the Agder Police District.