Tønsberg, historically Tunsberg, is a city and municipality in Vestfold county, eastern Norway, located around 102 km south-southwest of Oslo on the western coast of the Oslofjord near its mouth onto the Skagerrak. The administrative centre of the municipality is the city of Tønsberg. The city is the most populous metropolis in the district of Vestfold with a population of 52,419 in 2019. The municipality has a population of 56,293 and covers an area of 329 km2 in 2020. Tønsberg also serves as the seat for the County Governor of Vestfold og Telemark.