About this sound Sandefjord is a city and municipality in Vestfold county, Norway. The administrative centre of the municipality is the city of Sandefjord. The municipality of Sandefjord was established on 1 January 1838 (see formannskapsdistrikt). The rural municipality of Sandar was merged into the municipality of Sandefjord on 1 January 1968.The city is known for its rich Viking history and the prosperous whaling industry, which made Sandefjord the richest city in Norway.