The 7.9-square-kilometre (3.1 sq mi) island lies just south of the town of Lillesand with the Skaggerak to the east and the Blindleia strait and the mainland to the west.

[1] At 7.9 square kilometres (3.1 sq mi), Justøy is one of Agder county's largest islands.

Justøya is connected to the mainland by the narrow 116-metre (381 ft) long Justøybrua bridge, built in 1949.

There are Montessori school, Justøy Chapel,[2] cemetery, pension boarding house,[3] campsite,[4][5] and the summer shop in Brekkestø.

[1] In Nyberg, just north of Brekkestø, are the Festung Björkestraße ruins from World War II.