This state encompasses nearly the entirety of the volcanic Hawaiian Island chain, which is made up of hundreds of islands spread over 1,500 miles (2,400 km). At the southeastern end of the archipelago, the eight "main islands" are (from the northwest to southeast) Ni'ihau, Kaua'i, O'ahu, Moloka'i, Lana?i, Kaho'olawe, Maui, and Hawaii. The last is by far the largest, and is often called the "Big Island" or "Big Isle" to avoid confusion with the state as a whole. This archipelago is physiographically and ethnologically part of the Polynesian subregion of Oceania.

The volcanic activity and subsequent erosion created impressive geological features. The Big Island is notable as the worlds fifth highest island.

Because of the islands' volcanic formation, native life before human activity is said to have arrived by the "3 W's": wind (carried through the air), waves (brought by ocean currents), and wings (birds, insects, and whatever they brought with them). The isolation of the Hawaiian Islands in the middle of the Pacific Ocean, and the wide range of environments to be found on high islands located in and near the tropic, has resulted in a vast array of endemic flora and fauna. Hawaii has more endangered species per square mile and has lost a higher percent of its endemic species than anywhere else on Earth.