Østfold means the land on the eastern side of the Oslo Fjord The county is situated between the Oslo fjord and the Swedish border.
The terrain is largely farmland and low forested hills. Glomma, the longest river in Norway, empties into the sea in Østfold.
Old traces of stone age settlements have been found in this county. The population of Østfold is 256,668 and the capital is Moss, with a population of 27,732