Nihoa is part of the Hawaiian – Emperor seamount chain of volcanic islands, atolls, and seamounts starting from the island of Hawaiʻi in the southeast to the Aleutian Islands in the northwest.
 It is the youngest of ten islands in the uninhabited Northwestern Hawaiian Islands (NWHI), having formed 7.2 million years ago; the oldest, Kure Atoll, formed 30 million years ago.
 Over the millennia, Nihoa has experienced significant erosion; along with Necker, French Frigate Shoals, and Gardner Pinnacles, Nihoa is one of only four islands in the NWHI that still has an exposed basalt rock substrate.
Six valleys slant down from north to south, meeting at the south side of the island: West Valley, West Palm Valley, Miller Valley, Middle Valley, East Palm Valley, and East Valley.

Among features on Nihoa are  Dog's Head Peak (358 ft or 109 m), named for its likeness, and  Pinnacle Peak (626 ft or 191 m), a volcanic dike created when less resilient rock was eroded away and harder rock was open to the elements.
 The only flat area on the island is  Albatross Plateau, just below Miller's Peak.
 The Devil's Slide is a narrow cleft descending 700 feet (210 m) irrespective of the surrounding elevation.
 Extending northward from Albatross Plateau, it ends at the vertical cliffs with a 190-foot (60 m) drop straight down to the ocean below.
 In this chasm, rare ferns grow, along with several endemic species, including a giant cricket.
Nihoa is part of the Hawaiian – Emperor seamount chain of volcanic islands, atolls, and seamounts starting from the island of Hawaiʻi in the southeast to the Aleutian Islands in the northwest.  It is the youngest of ten islands in the uninhabited Northwestern Hawaiian Islands (NWHI), having formed 7.2 million years ago; the oldest, Kure Atoll, formed 30 million years ago.  Over the millennia, Nihoa has experienced significant erosion; along with Necker, French Frigate Shoals, and Gardner Pinnacles, Nihoa is one of only four islands in the NWHI that still has an exposed basalt rock substrate. Six valleys slant down from north to south, meeting at the south side of the island: West Valley, West Palm Valley, Miller Valley, Middle Valley, East Palm Valley, and East Valley.
Among features on Nihoa are  Dog's Head Peak (358 ft or 109 m), named for its likeness, and  Pinnacle Peak (626 ft or 191 m), a volcanic dike created when less resilient rock was eroded away and harder rock was open to the elements.  The only flat area on the island is  Albatross Plateau, just below Miller's Peak.  The Devil's Slide is a narrow cleft descending 700 feet (210 m) irrespective of the surrounding elevation.  Extending northward from Albatross Plateau, it ends at the vertical cliffs with a 190-foot (60 m) drop straight down to the ocean below.  In this chasm, rare ferns grow, along with several endemic species, including a giant cricket.
Nihoa