The Ōnohara Islands (大野原島, Ōnohara-jima) are a group of volcanic deserted islands located in the Philippine Sea approximately 180 kilometres (110 mi) south of Tokyo and 10 kilometres (6.2 mi) west of Miyake-jima, in the northern portion of the Izu archipelago, Japan.

The island is the remnant of an andesite lava dome with sheer sides, the only visible portion of a submarine volcanic caldera.

The above sea-level portion has a surface area of approximately 0.2 square kilometers, with a summit height of 114 metres (374 ft) on the main islet of Koyasu-shima (小安島).

Located in the Kuroshio Current, the area has abundant sea life, and is popular with sports fishermen and scuba divers.

The bombing was stopped after Jack Moyer wrote a letter to an associate of then-US President Harry S.