Moneron has an area of about 30 square kilometres (12 sq mi) and a highest point of 429 metres (1,407 ft). It is approximately 7.2 km (4.5 mi) long (N/S axis) by 5.5 km (3.4 mi) wide, and is located 41 nautical miles (76 km) from Sakhalin's port of Nevelsk and about 30 nautical miles (56 km) directly southwest of Sakhalin Island itself at the northeastern end of the Sea of Japan. It is the only landmass in the whole Tatar Straits. It has no permanent population.
The island was known as Todomoshiri ("island of sea lions") by its original Ainu inhabitants. It came under the daimyō of Matsumae clan in the 18th century and was known as Ishiyokotan; it got its current European name from a visit of the French navigator La Perouse, who named it Moneron after Paul Mérault Monneron, the chief engineer of his expedition.
Paul Moneron was tasked with mapping the island named after him. The first authentic map of Moneron Island was made later, in 1867, by Russian hydrographers who put it on the map of the Russian Empire. The expedition was led by one K. Staritsky, after whom the highest spot was named. Moneron Island was not Russian for long.
By 1907, the Japanese named it Kaibato (海馬島), in which Kai-ba is an on-yomi transliteration of the Ainu name. It is also known as "Todojima" (トド島), which is a direct usage of the Ainu pronunciation of the Sea Lion, with jima/shima (島) being added afterwards, which means island in traditional kun-yomi Japanese. Moneron Island is very close to Japan: On a clear day, you can see the Japanese Rishiri Island.
Fauna and flora
The island is a popular place for diving and for birds. Surrounded by steep cliffs and rocky islets, it is a haven for sea birds. The warm Tsushima Current brings abundant marine life to the surrounding waters and species normally found much further south abound.
In 2006, infrastructure was constructed to allow tourists to visit the island. The facilities are operated by the Moneron National Park, which is the first marine national park in Russia.