The Site is an extensive estuarine area at the mouth of Norway’s largest river, Glomma, characterized by shallow areas of brackish water with numerous small islands and skerries surrounded by sediments deposited by the river. The Site also includes meadows, grassland and forest areas. It is an important area for nesting, passage, moulting and wintering waterbirds, including swans and large numbers of ducks in autumn. In total, around 250 bird species have been recorded in the area, with 90 known to have bred. Øra supports nationally threatened bird and plant species and a high diversity of freshwater and sea fish, with 41 species recorded. The rare tentacled lagoon worm Alkmaria romijni has not been recorded elsewhere in Norway. The Site is used for livestock grazing and recreation; there is a birdwatching tower. Regulations prevent construction, hunting, drainage, and access to resting areas during sensitive periods.