Rusne island was formed by the last glacier before 14000–12000 years. A river was separated to the three branch - Skirvyte, Pakalne and Atmata. After floods silk collected on that island and formed fertile foodplain soil.

Relief is plain with micro rises and sockets. The top of island is 1,4 metres above sea’s level and lowest place, near Dumbe river is 0,2 metres under sea's level.

Island's area is becoming bigger. Coast is moving 30 metres every years.