Masfjorden is a municipality in the central part of Vestland county in Norway. The municipality is located in the Nordhordland district of the county. The administrative centre of the municipality is the village of Masfjordnes. Other villages in the municipality include Frøyset, Hosteland, Matre, and Solheim. The municipality is centered on the Masfjorden which almost divides the municipality completely into a north side and a south side. A cable ferry crosses the fjord from Masfjordnes to Duesund in the western part of the municipality. The Matre Hydroelectric Power Station is located in the eastern part of the municipality. The municipality is the 195th largest by area out of the 356 municipalities in Norway. Masfjorden is the 297th most populous municipality in Norway with a population of 1,629. The municipality's population density is and its population has decreased by 3.2% over the previous 10-year period. The parish of Masfjorden was established as a municipality on 1 March 1879 when it was separated from the large municipality of Lindås. Masfjorden was the northern part of Lindås, and its initial population was 2,336. During the 1960s, there were many municipal mergers across Norway due to the work of the Schei Committee. On 1 January 1964, the Einestrand, Eikebotn, and Kikallen area along the Austfjorden (population: 25) was transferred from Lindås to Masfjorden. The municipality (originally the parish) is named after the Masfjorden (Matrsfjǫrðr) since that fjord is a central geographical feature of the municipality. The first element is the genitive case of the old (uncompounded) name of the fjord: Matr. That name is identical to the word matr which means "food". The last element is fjǫrðr which means "fjord" or "firth". Therefore, the meaning of the name is "the fjord that's full of food (fish)". The village of Matre lies at the inner end of the fjord, and that name has a similar origin. The coat of arms was granted on 28 September 1990. The official blazon is "Gules, three clasps Or in pall" (På raud grunn tre gule heldrer stilte i trepass).