In 1969 Tölö was merged into the City of Kungsbacka. In 1971 the municipality was created when the city amalgamated with Särö. The final step was taken in 1974 when three more former municipalities were added to form the new entity.
A local geographical landmark is the glacial ridge Fjärås bräcka, to the south of Kungsbacka, but it is the coast that is the predominant geographical feature. The municipality receives its drinking water from the nearby lake Lygnern; the water undergoes a natural filtering process as it trickles through the ridge, contributing to its quality.