Roca Partida (English: Split Rock) ranks as the smallest of the four Revillagigedo Islands, part of the Free and Sovereign State of Colima in Mexico.
[citation needed] Divers must obtain permits from the Mexican Armed Forces to enter the military zone surrounding the island.
Erosion over millennia reduced Roca Partida to a piece of bare rock, devoid of terrestrial vegetation.
Several species of seabird breed on the rock, including the Nazca booby (Sula granti), which probably ventures little farther to the northeast; the Northeast Pacific brown booby (Sula leucogaster brewsteri); the East Pacific sooty tern (Onychoprion fuscatus crissalis), a doubtfully distinct subspecies; and the East Pacific brown noddy (Anous stolidus ridgwayi).
[2] The island's first reported sighting was in November 1542 by the Spanish expedition of Ruy López de Villalobos, who charted it with its present-day name.