Pearl Harbor is a harbor located on the island of Oahu in the US state of Hawaii. It is situated on the southern shore of the island, about five miles (8 kilometers) west of the state capital, Honolulu. The harbor is a sheltered body of water that covers an area of approximately 19 square kilometers (7 square miles). It is made up of several interconnected bays and inlets, and is surrounded by the Waianae Mountains to the west and Koolau Mountains to the east. The entrance to the harbor is marked by a narrow channel called the Pearl Harbor Bar.