Geography

The Republic of Indonesia is the largest archipelago country in the world, comprising 17,508 islands stretching along 5,120 kilometers from east to west, and 1,760 kilometers from north to south. The islands scatter over more than one tenth of the equator between Southeast Asia and Australia, covering a land area of around 2 million square kilometers and territorial waters nearly four time of that size.

1. Main islands : Java, Bali, Sumatera, Kalimantan, Sulawesi, and Papua. There are two large groupings of smaller islands: Maluku and Nusa Tenggara.

2. Main cities :

1. Jakarta, the capital city of the Republic of Indonesia located on the north west coast Java, is the government and an economic center of Indonesia.
2. Surabaya, Indonesia's second largest city located in East Java, is a leading industrial center and port.
3. Medan in North Sumatera, is the third largest city near of Singapore/ Selat Malaka.
4. Other important cities are Bandung, Denpasar, Semarang, Yogyakarta, Padang, Palembang, Makassar, Manado, Banjarmasin, Balikpapan, and Jayapura.

At 1,919,440 square kilometers (741,050 sq mi), Indonesia is the world's 16th-largest country in terms of land area.[Its average population density is 134 people per square kilometer (347 per sq mi), 79th in the world, although Java, the world's most populous island,has a population density of 940 people per square kilometer (2,435 per sq mi). At 4,884 meters (16,024 ft), Puncak Jaya in Papua is Indonesia's highest peak, and Lake Toba in Sumatra its largest lake, with an area of 1,145 square kilometers (442 sq mi). The country's largest rivers are in Kalimantan, and include the Mahakam and Barito; such rivers are communication and transport links between the island's river settlements.

The archipelago of Indonesia comprises about 17,508 big and small islands, of which only about 6,000 are inhabited. Five main islands and 30 smaller island groups are home to the majority of the population. The main islands are Sumatera (425,606 km²), Kalimantan (539,460 km²), Sulawesi (174,219 km²), Irian Jaya (421,981 km²), and Java (129,187 km²) which is home to about 70% of the country’s population. The archipelago lies on tropical zone of Southeast Asia. The equator passes through the islands of Sumatera, Kalimantan, Sulawesi, and Halmahera. Geographically, the archipelago is situated between 06^o08 north latitude to 11^o15 south latitude and 94^o45 to 141^o05 east longitude; between two continents: Asia and Australia; between two oceans: Indian and Pacific; and on the traditional trading crossroads.

Stretching along the equator of about 8,000 km long, it is the same width to the North American Mainland, or Australia Continent, or West European Continent. Total territorial area is 9.8 million km², a large part of which (7.9 million km² or 81%) is sea, while the rest (1.9 million km2 or 19%) is terrestrial land. Total coastline length of all islands is 54,716 km. Having such figures, Indonesia is recognized as the greatest maritime country in the world.

The archipelago of Indonesia is situated on the matching point of the two world greatest volcanic ranges, the Mediterranean from the west and Circum Pacific from the northeast, by which the volcanic pattern, physiography, and geomorphology of the archipelago are strongly influenced.

There are about 400 mounts, most of which are volcanoes - either active or inactive ones - forming a bow of mountain ranges along the array of islands on the southern archipelago stretching from Sumatera, Krakatau on the Straits of Sunda, Java, Bali, Lombok, Sumbawa, and Flores. Kalimantan is the only island where volcano does not exist; instead, dense tropical rainforest naturally developed on the middle-range and peat-swamp ecosystems on the lowland. The highest summit of the archipelago is Mount Jayawijaya, about 5,000 m above sea level, where snow can be permanently found.

Facing the Indian Ocean, most of the coastlines of these islands are steep cliffs with very limited sand dunes. On the other hand, the inner northward coastlines are relatively flat, with substantially rapid coast expansion due to excessive sedimentation. On this type of coastline, mangrove forest communities exist, and brackish-water fish culture takes place on relatively developed areas.