Borøya is an
island
An island (or isle) is an isolated piece of habitat that is surrounded by a dramatically different habitat, such as water. Very small islands such as emergent land features on atolls can be called islets, skerries, cays or keys. An island ...
in the western section of
Oslofjord
The Oslofjord (, ; en, Oslo Fjord) is an inlet in the south-east of Norway, stretching from an imaginary line between the and lighthouses and down to in the south to Oslo in the north. It is part of the Skagerrak strait, connecting the Nor ...
(Vestfjorden), within the borders of the municipality of
Bærum
Bærum () is a municipality in the Greater Oslo Region in Norway that forms an affluent suburb of Oslo on the west coast of the city. Bærum is Norway's fifth largest municipality with a population of 128,760 (2021). It is part of the electoral ...
.
Islands of Viken (county)
Geography of Bærum
{{Viken-geo-stub