Adjacent to the refuge is Capella Island, about half the size of Buck, owned by the territorial government.

The refuge is characterized by a thorn scrub habitat with rocky coastline surrounded by spectacular reefs.

A lighthouse (still maintained by the United States Coast Guard) stands over 45 acres (180,000 m2) of cactus and grassland.

The island was transferred to the United States Fish and Wildlife Service due to "its value for migratory birds."

The surrounding waters contain reefs and a shipwreck that attract large numbers of snorkelers, divers, and boaters.