The National Park samples the best of American Samoa scenery, shorelines, reefs, and rainforest. In essence, it is really “three parks” on four separate islands. All the units have fine scenery and tropical rainforests. Lata Mountain on Ta’u excels in its wild and remote forests, free-flowing streams, and rugged coastline. Ofu and Olosega have the most accessible coral reefs and miles of breathtakingly beautiful beaches. Tutuila has road accessible forests, native wildlife, and scenic coastline.

All the four islands are extinct volcanoes heavily eroded to rugged peaks.  They were formed as the "Pacific plate" moved across a stationary hot spot where eruptions from the Earth's mantle pierced the lithosphere forming a line of volcanic islands.