Sandnessjøen (historically named Stamnes) is a former municipality in Nordland county, Norway.

Originally, it consisted of the northern part of the island of Alsta and the mainland area around the Leirfjorden.

During the 1960s, there were many municipal mergers across Norway due to the work of the Schei Committee.

Thus it is referring to the large mast-like peninsula on which the village of Stamnes was located.

At the time of the municipal dissolution, it was part of the Alstahaug prestegjeld and the Nord-Helgeland prosti (deanery) in the Diocese of Sør-Hålogaland.

The municipal council (Herredsstyre) of Sandnessjøen was made up of 21 representatives that were elected to four year terms.

The tables below show the historical composition of the council by political party.