The state of Koror contains about 70% of the population of the country. The nation's former capital and largest town, also called Koror, is located here. The town has a population of 11,200 and is located at 7°20′32″N 134°28′38″E / 7.34222°N 134.47719°E / 7.34222; 134.47719Coordinates: 7°20′32″N 134°28′38″E / 7.34222°N 134.47719°E / 7.34222; 134.47719. On 7 October 2006, Ngerulmud replaced Koror as Palau's capital city.
The first sighting of Koror, Babeldaob, and Peleliu recorded by Westerners was by the Spanish expedition of Ruy López de Villalobos at the end of January, 1543. They were then charted as Los Arrecifes (The Reefs in Spanish). In November and December 1710 these three islands were again visited and explored by a Spanish missionary expedition commanded by Sargento Mayor Francisco Padilla on board the patache Santísima Trinidad. Two years later they were explored in detail by the expedition of Spanish naval officer Bernardo de Egoy.
The island of Koror is connected by bridges to three neighbouring islands:
Koror Island is also connected by the Koror–Babeldaob Bridge to the state of Airai in the island of Babeldaob, where Palau International Airport is located.
Besides the former capital Koror and the town of Meyuns, there are a total of 11 hamlets in the state of Koror:
Koror was the capital of the former Japanese mandated territory of Nanyo.
Much of Palau's economy comes from tourism. The Rock Islands of Palau are all located in the state. Scuba diving shops and facilities are located all over Koror. Accommodation like hotels, bars, restaurants, cafes, and resorts are all available. Dolphins Pacific, the world's largest dolphin research facility, is open for tourists who are interested in swimming and interacting with trained dolphins. Most tourists to Palau stay in Koror, which is the centre for Palau's resort services and house modern conveniences. Koror has businesses that cater to speakers of many languages.
By 2001, the Koror Jail, Palau's only correctional facility, has become a tourist destination thanks to inmates who create and sell elaborate wooden storyboards at a retail facility located on the jail's grounds.
In 2002, of the 17,000 people living in Palau, 68% lived in Koror.
Belau Air has its headquarters in Koror, as did the short-lived Pacific Flier in 2010.
Koror is twinned with: