Sensuijima Island
The island of Sensuijima is made up of rock created by intense volcanic activity over 90 million years ago, when the Japanese archipelago was still part of the Eurasian continent. The island’s topography and the presence and distribution of certain rocks offer insights into the region's geological history, which has included periods of significant volcanic and seismic activity. Features such as eroded sea caves and the Sensui Formation are designated Prefectural Natural Monuments.
Hiking trails lead to the island’s three peaks, where there are vantage points with views of the surrounding sea, islands, and the port town of Tomonoura on the eastern coast of the Numakuma Peninsula.
Sensuijima is part of both Tomo Park and Setonaikai National Park. Tomo Park is a prefectural park that includes Sensuijima, several neighboring islands, and parts of the Numakuma Peninsula. It is designated a National Place of Scenic Beauty for its dramatic coastlines and island views.
Setonaikai National Park is one of the largest national parks in the country. It covers over 9,000 square kilometers of land and water in the Seto Inland Sea across 11 prefectures, including Hiroshima, Osaka, and Fukuoka. Encompassing approximately 1,000 islands, the park has a diverse range of protected coastal and island landscapes of cultural and natural importance, from Itsukushima Shrine in Hiroshima to the Naruto whirlpools in Tokushima.