Viken was a short-lived county in Norway that existed from 1 January 2020 to 1 January 2024. Its name was derived from the historical region in modern Sweden. The county was located in Eastern Norway when it was established on 1 January 2020 by the merger of Akershus, Buskerud and Østfold with the addition of the municipalities of Jevnaker, Lunner and the former Svelvik Municipality.