Java Trench, also Known as Sunda Trench, deep submarine depression in the eastern Indian Ocean that extends some 2,000 miles (3,200 km) in a northwest-southeast arc along the southwestern and southern Indonesian archipelago. It is located about 190 miles (305 km) off the southwestern coasts of the islands of Sumatra and Java, stretching eastward south of the western Lesser Sunda Islands. To the northwest the trench merges with a system of islands and continental shelves that eventually extend into the Ganges River delta. For about half its length, off of Sumatra, it is divided into two parallel troughs by an underwater ridge, and much of the trench is at least partially filled with sediments. Its slopes exceed 10° and descend to a maximum depth of 24,440 feet (7,450 metres), the deepest point in the Indian Ocean.