Oahu is located near the center of the Pacific Ocean between the islands of Kauai and Maui. While many people might assume that Hawaii is close to the west of coast of the mainland United States, the island of Oahu actually lies about 2,390 miles west of the San Francisco, California. It is the second oldest of the Hawaiian Islands and is made up of two volcanoes, known as the Waianae and the Koolau mountains. The overall size and shape of Oahu was greatly influenced by two large landslides that about 1/3 of the northeastern portion of the island and another 1/2 of the western side. However, there are other smaller forms of volcanoes which are now extinct throughout the island. These volcanic cones are usually no bigger than 1,000 feet high and a mile in diameter. A few of the famous volcanic cones include, Leahi (Diamond Head) and Punchbowl Crater.
The Waianae mountain range lies to the west and is parallel to Ko'olau, which lies to the east. The Waianae mountain range separates Central Oahu region from the Leeward Coast region and it is the oldest part of Oahu at about four million years old. In comparison, the Ko'olau mountains ranges through the length of the island's eastern coast and is thus about 34 miles long. This mountain range separates the Windward Coast from Central Oahu. On the east side, through thousands of years of erosion, there are many cliffs, ridges, and rock faces. Oahu's physical geography is dominated by its shoreline. While Oahu is a total of 44 miles long and 30 miles wide, it has a shoreline that is 227 miles long. Additionally, the highest elevation point is Mt. Ka'ala in the Waianae range, which is 4,003 feet above sea level.