[1] The island is located approximately 30 kilometres (19 mi) west of the city of Murakami in northern Niigata Prefecture.

The Matsura clan of northern Kyushu, noted pirates and sea traders, began to occupy the eastern shore of the island from the 9th century, gradually pushing the Emishi out.

During the Boshin War, the Schnell brothers offloaded weapons for Shonai Domain at Awashima.

After the Meiji restoration, the village of Asahimaura was created in 1909 as part of Iwafune, District, Niigata Prefecture.

The island has been recognised as an Important Bird Area (IBA) by BirdLife International because it supports a large breeding colony of streaked shearwaters.