Gnago Island is a location on Bajor and the site of a Bajoran research compound.
In 2372, Keiko O'Brien was asked to investigate a newly discovered kind of flora on Gnago Island. Taking Molly with her, Keiko's assignment coincided with a disease known as the Wrath of the Prophets striking Bajor. Molly became infected with the Wrath, but was healed when the crew of Deep Space 9 discovered a cure. (DS9 novel: Wrath of the Prophets)