The Kauai island

Kauai is geologically the oldest of the main Hawaiian Islands. With an area of 562.3 square miles (1,456.4 km), it is the fourth-largest of these islands and the 21st largest island in the United States. Known also as the "Garden Isle", Kauai lies 105 miles (169 km) across the Kauai Channel, northwest of Oahu. This island is the site of Waives Canyon State Park. The United States Census Bureau defines Kauai as census tracts 401 through 409 of Kauai County, Hawaii, which comprises the entire county except for the islands of Kabul, Li hue and Haunting. The 2010 United States Census population of the island was 67,091.The most populous town was Kappa.