To the west, it starts between the villages of Salhus and Frekhaug, where the Byfjorden meets the Herdlefjorden.

It acts as one of the borders between the districts of Midhordland to the south and Nordhordland to the north.

[1] The fjord takes its name from the village area of Salhus, which during the Viking Age in the early 12th century there was an inn (known at the time as a sáluhus), which would give name to the place.

It acted as a transport hub for Nordhordland, and was a small market town.

Starting on 7 July 1936, a ferry service ran between the villages of Isdalstø and Steinestø.