Onsala is a locality situated in Kungsbacka Municipality, Halland County, Sweden, with 11,951 inhabitants in 2010. It is also a 14 km long peninsula on the west coast of Sweden, facing Kattegat, 40 kilometres (25 mi) south of Gothenburg. It dates back to the age of the vikings and was originally an area devoted to the god Odin, the name being a corruption of the old norse Odin's Sala. In English "The Halls of Odin"