Sandnessjøen is a town and the administrative centre of the municipality of Alstahaug in Nordland county, Norway. Sandnessjøen was granted town status in 1788. Sandnessjøen is located on the island of Alsta, just west of the De syv søstre (The Seven Sisters) mountain range. The 4.0-square-kilometre (990-acre) town has a population (2013) of 5,930. The population density is 1,548 inhabitants per square kilometre (4,010/sq mi).Sandnessjøen Airport, Stokka is located south of the town.