Central American island of Panama in the Pacific Ocean. Lying 15 miles (24 km) offshore and separated from the mainland by the Gulf of Montijo on the east and the Gulf of Chiriquí on the northwest, the island measures about 20 miles from north to south and 10 miles from east to west. It has an area of 191 square miles (494 square km) and rises to a maximum elevation of 1,400 feet (425 metres). Coiba was the site of a notorious penitentiary (closed in 2004). Now a national park, the island was designated a UNESCO World Heritage site in 2005.