[7] Micronesian altars, graves, tools, and pottery were discovered on North Iwo Jima by a Tokyo research group in 1991.

[8] Commanding the carrack San Juan de Letrán, the Spanish explorer Bernardo de la Torre almost certainly sighted the Volcano Islands[9] at some point between 25 September and 2 October 1543 while making another failed attempt to sail east across the Pacific from the Philippines to New Spain.

[13] Over the next century, other Spanish sailors passed the islands—particularly once Alonso de Arellano found a safe northeastern route back to Mexico from the Philippines—without settling or formally claiming them.

They lived in two villages, Ishino or Ishinomura on the east and Nishi or Nishimura on the west,[14] which were unincorporated until they were formally added to Iōtō in 1940.

Four US Navy aviators—Scott Zellem, Patrick Myrick, James Pupplo, and Joshua Showalter—from the John C. Stennis died when their S-3B Viking crashed into North Iwo Jima on 10 August 2004 during a naval exercise.