The Oslofjord (Norwegian: Oslofjorden, English: Oslo Fjord) is an inlet in the south-east of Norway, stretching from an imaginary line between the Torbjørnskjærand Færder lighthouses and down to Langesund in the south to Oslo in the north. It is part of the Skagerrak strait, connecting the North Sea and the Kattegat sea area, which leads to the Baltic Sea

The Oslofjord is not a fjord in the geological sense - in Norwegian the term fjord can refer to a wide range of waterways. The bay is divided into the inner (indre) and outer (ytre) Oslofjord at the point of the 17 by 1 kilometre (10.56 by 0.62 mi) Drøbak Sound


Each of the islands in the innermost part of the fjord has its own identity and distinguishing history. Among them are Hovedøya, Lindøya, Nakholmen, Bleikøya, Gressholmen, and Langøyene.

These islands can be reached with the Oslo-boats from Aker Brygge. Hovedøya contains monastery ruins, Gressholmen for its rabbits, Nakholmen, Bleikøya, Lindøya for their cosy cabins at the water’s edge, and finally Langøyene for its camping possibilities and beach.

The inner part of the Oslofjord has steep and forest covered hill slopes down towards the fjord.