Oahu -- Island Overview

The most populated of the Hawaiian islands, Oahu is home to approximately three-quarters of Hawaii’s million-plus residents. Oahu is the location of the state capital, Honolulu, a beautiful and modern city which is also the business and financial center of the state. Also to be found on Oahu are Waikiki Beach, arguably the world’s most famous beach, and The U.S. Naval Base at Pearl Harbor, where one of the most important military battles in world history took place.

Oahu, like all of the Hawaiian Islands, was formed by massive volcanoes over four million years ago. The volcanoes that formed Oahu are now dormant, but they left their signature in the form of the Koolau and Waianae mountain chains which run right down the middle and western parts of the island, respectively (if you want to see an active volcano, you will have to visit The "Big Island" of Hawaii). These mountains effectively shelter the southern and western (or leeward) sides of the island from the southwesterly trade winds that bring in rainy weather to the windward side of the island. Before the clouds can get to the leeward side of the island, they have to dump all of their precipitation on the windward side. This allows the leeward side of Oahu to be lush and tropical, and the southern side to be sunny, with a warm climate. Not surprisingly, Honolulu and Waikiki sprouted on the pleasant leeward side.