østfold

Østfold was a county in southeastern Norway, located along the eastern shore of the Oslofjord and extending inland toward the Swedish border. It bordered Akershus and Oslo to the west and Sweden to the east. The region included towns such as Fredrikstad, Sarpsborg, Moss and Halden, together with rural areas of forests, farmland and archipelagoes. The name means "east fjord," reflecting its position at the eastern end of the Oslofjord.

Østfold existed as an administrative unit for centuries. On 1 January 2020 it merged with Akershus and Buskerud to form the larger Viken county as part of a nationwide regional reform. The county contained a mix of coastal and inland municipalities, with industry, shipping and agriculture as traditional economic bases.

Transport and infrastructure included the Østfold Line railway connecting Oslo with Halden and Sweden, as well as major highways and coastal ferries that link towns along the Oslofjord. The coastline with its islands and waterways supports tourism and local commerce.

Historically significant sites include fortified towns and museums in Fredrikstad and Sarpsborg. While now part of Viken, Østfold remains a recognizable historical and geographic region in Norwegian reference material and local identity.