Vestfold is a county in Norway, bordering Buskerud and Telemark. The county administration is in Tønsberg. Vestfold is located west of the Oslofjord, as the name indicates. It includes many smaller, but well-known towns in Norway, such as Larvik, Sandefjord, Tønsberg and Horten. The river Numedalslågen runs through the district. Many islands are located at the coast. Vestfold is mostly dominated by lowland and is among the best agricultural areas of Norway. Winters last about three months, while pleasant summer temperatures last from May to September, with a July average of 17°C (Tønsberg climate).