The 18.3-square-kilometre (7.1 sq mi) island is located in Ringsaker Municipality in Innlandet county, Norway.

The island is located south of the Nes peninsula, and it has been connected to the mainland by the Nessundet Bridge since 1957.

Another old farm is Eik ('oak') which is the source of the name of the tallest hill on the island: Eksberget.

The Old Norse forms of the name were Helgøy and Øyin helga, both meaning 'holy island'.

The farm name Hovin (Old Norse: Hofvin - later re-named Hovinsholm) on the southern tip of the island is a compound of hof which means "pagan temple (for the Norse gods)" and vin which means "meadow".