Prehistoric tools and carved stones, discovered on North Iwo Jima at the end of the 20th century, as well as stone tools discovered on Chichi-jima, indicate the islands might have been populated in ancient times.
Penemuan alat prasejarah dan batu berukir di Kita Iwo Jima pada akhir abad ke-20, serta alat-alat batu di Chichi-jima menunjukkan bahwa kepulauan ini pada zaman kuno mungkin telah dihuni manusia.