Onsala is a locality situated in Kungsbacka Municipality, Halland County, Sweden, with 11,951 inhabitants in 2010. It is also the biggest peninsula in Sweden, 40 kilometres (25 mi) south of Gothenburg.
The biggest village is Gottskär, in older days a fishing village, and which today has a few restaurants and a leisure boat harbour. Lars Gathenhielm was born in the old parish of Onsala.They are interred in a basement crypt beneath the smaller tower of the church. Their white sarcophagi have carved "jolly rogers" at the foot end.Onsala is also home to the Onsala Space Observatory, the Swedish national radio observatory.