Over a century of study in American Samoa has built a foundation of coral reef ecology within the region. However, this work has been restricted to shallow coral reefs (SCRs; <30 m) until recently, where a few studies have started describing American Samoa’s mesophotic coral ecosystems (MCEs). MCEs are defined as coral reef communities with zooxanthellate corals and associated biotic assemblages between 30 and 150 m depth. Mapping efforts within the territory have documented habitat characteristics for SCRs, as well as MCEs. We estimate that American Samoa has 451.5 km² of marine habitat between the shoreline and 150 m depth.