Viken is a county under disestablishment in Eastern Norway that was established on 1 January 2020 by the merger of Akershus, Buskerud, and Østfold with the addition of three other municipalities. Viken was controversial from the onset, with an approval rating of about 20% in the region, and the merger was resisted by all the three counties. Viken has been compared to gerrymandering. The county executive of Viken determined in 2019, before the merger took effect, that the disestablishment of Viken is its main political goal, and the formal process to dissolve Viken was initiated by the county executive in 2021 following the 2021 Norwegian parliamentary election, where the parties that seek to reverse the merger won a majority. The political platform of the government of Jonas Gahr Støre states that the government will dissolve Viken and reestablish Akershus, Buskerud and Østfold based on a request from the county itself. On 22 February 2022 the regional assembly of Viken approved the formal request to disestablish Viken.
Viken was home to over 1.2 million people, or 23% of the national population. The county seat is the national capital, Oslo, which is an enclave of Viken and is not part of the county. Oslo had been the seat of Akershus county since the Middle Ages. All of Viken is located within the historical Akershus, which included much of Eastern Norway. Viken takes its name from the historical region of Viken, which has been defined as an area in Bohuslän in today's western Sweden since the Middle Ages.
Both its creation and its name are subjects of strong controversy, and Viken is opposed by the counties concerned and perceived as lacking legitimacy; the elected regional assembly and county executive of Viken have declared the disestablishment of Viken in 2021 as the main political goal of Viken, while refusing to do anything to merge the counties in practice. The governing platform of Viken describes Viken as "an ill-considered construction"; in practice, the existing counties will continue to function with separate county administrations based on their existing infrastructure, in anticipation of their formal reestablishment.
In the 2021 parliamentary election, the parties that seek to dissolve Viken won a majority, and the Centre Party made the disestablishment of Viken a condition for participating in a new government. Immediately after the election, the county executive initiated the process to dissolve Viken.