Oahu is the third largest and the most developed, have a total land area of 6467 square miles. Like other islands of Hawaii, Oahu is the tip of an underwater mountain. The island is roughly shaped like an elephant's head, with the Waianae Range on the west, and the long Ko`olau Range on the east of the island.

Oahu is not the largest, but the main island of Hawaii. It is the most populated island and hosts five million visitors a year. Honolulu, the capital of Hawaii is situated here on Oahu. Honolulu boasts about 80% of the population of Hawaii.