Indonesia, country located off the coast of mainland Southeast Asia in the Indian and Pacific oceans. It is an archipelago that lies across the Equator and spans a distance equivalent to one-eighth of Earth’s circumference. It is an an economic and cultural crossroads.

The Indonesian archipelago represents one of the most unusual areas in the world: it encompasses a major juncture of Earth’s tectonic plates, spans two faunal realms, and has for millennia served as a nexus of the peoples and cultures of Oceania and mainland Asia. These factors have created a highly diverse environment and society that sometimes seem united only by susceptibility to seismic and volcanic activity, close proximity to the sea, and a moist, tropical climate. Nevertheless, a centralized government and a common language have provided Indonesia with unity.

Indonesia is the largest country in Southeast Asia, with a maximum dimension from east to west of about 3,200 miles (5,100 km) and an extent from north to south of 1,100 miles (1,800 km). Indonesia is composed of some 17,500 islands, of which more than 7,000 are uninhabited. 

There are over 100 active volcanoes in Indonesia and hundreds more that are considered extinct. Krakatoa, Indonesian Krakatau, volcano on Rakata Island in the Sunda Strait between Java and Sumatra, Indonesia. Its explosive eruption in 1883 was one of the most catastrophic in history. 

Indonesia can be grouped into the

Greater Sunda Islands of 

• Sumatra (Sumatera)
• Java (Jawa)
• the southern extent of Borneo (Kalimantan),
• Celebes (Sulawesi)

and the Lesser Sunda Islands (Nusa Tenggara) of Bali and a chain of islands that runs eastward through Timor

the Moluccas (Maluku) between Celebes and the island of New Guinea

and the western extent of New Guinea (generally known as Papua).

The capital, Jakarta, is located near the northwestern coast of Java. In the early 21st century Indonesia was the most populous country in Southeast Asia and the fourth most populous in the world.