Ruhnu, an island in the middle part of the Gulf of Riga; 11.4 km², 5.5 km in length, 3.5 km in width, circumference 23.3 km. The closest point to the island on the mainland is Kolka nose (Kolkasrags) in Courland (37 km), 54 km to Kihnu Island, 70 km to Kuressaare and 96 km to Pärnu. Together with the surrounding islets (about 30 of them, the largest of which is Holm) it makes up Ruhnu rural municipality in Saare County. 

The island of Ruhnu is a protruding part of a north-west-south-east-directional drumlin-like ridge situated in the deep central part of the Gulf of Riga. The north-eastern half of the island is higher and the dunes there (the highest point is Haubjerre dune ridge, 28m, location of the lighthouse) are covered with pine trees. The coast there has some up to 10 m tall coastal erosion terraces with Devonian sandstone outcrops at places. The south-western half is lower, there is canebrake on the coast and black alder forest inland. This is where the majority of agricultural land lies on the island. On the eastern side there is a 5–15 m wide loose sand beach covered in low dune strips.

The nature on Ruhnu has been shaped by distinct climatic and hydrological conditions. Ruhnu is very open to winds and winds thus have a great influence on the island – the waves and currents caused by wind have influenced coastal processes and the movement of sediments. Ruhnu is frequently struck by storms (especially fierce storms devastated Ruhnu in 1749, 1810, 1836, 1910, 1969, 2005).The climate is marine and somewhat milder than on the Estonian mainland.

Over 180 species of birds and about 540 species of vascular plants have been registered on Ruhnu. About 60% of the territory of the island is made up by forest, about 7% by fields, 13% by grasslands, and 18% by dunes and canebrake. Majority of the land (60%) has been returned or is to be returned to legitimate owners of Swedish decent, 7% belongs to Estonian citizens (as of 2003).

One of the rarest species on the island is the natterjack toad (I conservation class).

Eastern coast of the Ruhnu Island

The dunes are covered with pine trees

Created in 2014