The parish of Christianssund was established as a municipality on 1 January 1838 (see formannskapsdistrikt). On 1 January 1897, the Grip archipelago was separated from Kristiansund Municipality to become a separate municipality. On 1 January 1964, Kristiansund Municipality was merged with the tiny Grip Municipality (population: 104) to the northwest and the Dale area of Bremsnes Municipality on Nordlandet island (population: 963).[3] The neighboring Frei Municipality was merged with Kristiansund on 1 January 2008 creating a much larger Kristiansund Municipality.