About 15% of Sweden lies north of the Arctic Circle. Southern Sweden is predominantly agricultural, with increasing forest coverage northward. Around 65% of Sweden's total land area is covered with forests. The highest population density is in the Öresund Region in southern Sweden, along the western coast up to central Bohuslän, and in the valley of lake Mälaren and Stockholm. Gotland and Öland are Sweden's largest islands; Vänern and Vättern are its largest lakes. Vänern is the third largest in Europe, after Lake Ladoga and Lake Onega in Russia.