Tønsberg, historically known as Tunsberg, is a city located in Tønsberg Municipality within the Vestfold county of Norway. It is situated on the western coast of the Oslofjord near its mouth onto the Skagerrak, approximately 102 kilometres south-southwest of the capital city, Oslo.
The city serves as the most populous metropolis in Vestfold county and functions as the administrative centre for the region. It is also the seat of the County Governor of Vestfold og Telemark.