Oahu, known as "The Gathering Place", is the third largest of the Hawaiian Islands; however, it is the most populous of the islands in the U.S. state of Hawaii while also having the primary and only intercontinental Honolulu International Airport. The state capital, Honolulu, is on Oʻahu's southeast coast. Including small close-in offshore islands such as Ford Island and the islands in Kaneohe Bay and off the eastern coast, it has a total land area of 596.7 square miles, making it the 20th largest island in the United States.In the greatest dimension, this volcanic island is 44 miles long and 30 miles across.The length of the shoreline is 227 miles.The island is the result of two separate shield volcanoes: Waiʻanae and Koʻolau, with a broad "valley" or saddle between them. The highest point is Mt. Ka'ala in the Waiʻanae Range, rising to 4,003 feet above sea level.The island is home to about 953,207 people. Oʻahu has for a long time been known as "The Gathering Place". However, the term Oʻahu has no confirmed meaning in Hawaiian, other than that of the place itself.Ancient Hawaiian tradition attributes the name's origin in the legend of Hawaiʻiloa, the Polynesian navigator credited with discovery of the Hawaiian Islands. The story relates that he named the island after a son.Residents of Oʻahu refer to themselves as "locals", no matter their ancestry.The city of Honolulu—largest city, state capital, and main deepwater marine port for the State of Hawaiʻi—is located here. As a jurisdictional unit, the entire island of Oʻahu is in the City & County of Honolulu, although as a place name, Honolulu occupies only a portion of the southeast end of the island.Well-known features found on Oʻahu include Waikīkī, Pearl Harbor, Diamond Head, Hanauma Bay, Kāneʻohe Bay, Kailua Bay, North Shore.Being roughly diamond-shaped, surrounded by ocean and divided by mountain ranges, directions on Oʻahu are not generally described with the compass directions found throughout the world. Locals instead use "ewa" to mean toward the western tip of the island, "Diamond Head" to be toward the eastern tip, "mauka" is toward the mountains and "makai" toward the sea.Locals consider the island to be divided into various areas, which may overlap. The most commonly accepted areas are the "City", "Town" or "Town side", which is the metropolitan area from Halawa to the area below Diamond Head; "West Oʻahu," which goes from Pearl Harbor to Kapolei and Ewa and may include the Makaha and Waianae areas; the "North Shore"the "Windward Side" the "East Side" (the eastern portion of the island, including both the Windward Side and the area east of Diamond Head; and "The Valley" or "Central Oʻahu" which runs northwest from Pearl Harbor toward Haleiwa. These terms are somewhat flexible, depending on the area in which the user lives, and are used in a mostly general way. Oahu is also known for having the longest rain shower in history with over 200 days spent with continuous rain. Kaneohe Ranch, Oahu, Hawaii reported 247 straight days with rain from August 27, 1993 to April 30, 1994.The old Kingdom of Oʻahu was once ruled by the most ancient Aliʻi in all of the Hawaiian Islands. The first great king of Oʻahu was Mailikukahi, the law maker, who was followed by many generation of monarchs. Kualii was the first of the warlike kings and so were his sons. In 1773, the throne fell upon Kahahana, the son of Elani of Ewa. In 1783 Kahekili II, King of Maui, conquered Oʻahu and deposed the reigning family and then made his son Kalanikupule king of Oʻahu. Kamehameha the Great would conquer in the mountain Kalanikupule's force in the Battle of Nuʻuanu. Kamehameha founded the Kingdom of Hawaiʻi with the conquest of Oʻahu in 1795. Hawaiʻi would not be unified until the islands of Kauaʻi and Niʻihau surrendered under King Kaumualii in 1810. Kamehameha III moved his capital from Lāhainā, on Maui to Honolulu, Oʻahu in 1845. ʻIolani Palace, built later by other members of the royal family, is still standing, and is the only royal palace on American soil.