Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian and Pacific oceans.
It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guinea. Indonesia is the world's largest archipelagic state and the 14th-largest country by area, at 1,904,569 square kilometres (735,358 square miles).

With over 280 million people, Indonesia is the world's fourth-most-populous country and the most populous Muslim-majority country. Java, the world's most populous island, is home to more than half of the country's population. Despite its large population and densely populated regions, Indonesia has vast areas of wilderness that support one of the world's highest levels of biodiversity. The Indonesian archipelago has been a valuable region for trade since at least the seventh century when Sumatra's Srivijaya and later Java's Majapahit kingdoms engaged in commerce with entities from mainland China and the Indian subcontinent. Over the centuries, local rulers assimilated foreign influences, leading to the flourishing of Hindu and Buddhist kingdoms. Sunni traders and Sufi scholars later brought Islam, and European powers fought one another to monopolise trade in the Spice Islands of Maluku during the Age of Discovery. Following three and a half centuries of Dutch colonialism, Indonesia secured its independence after World War II. Indonesia's history has since been turbulent, with challenges posed by natural disasters, corruption, separatism, a democratisation process, and periods of rapid economic growth. Indonesia consists of thousands of distinct native ethnic and hundreds of linguistic groups, with Javanese being the largest. A shared identity has developed with the motto "Bhinneka Tunggal Ika" ("Unity in Diversity" literally, "many, yet one"), defined by a national language, cultural diversity, religious pluralism within a Muslim-majority population, and a history of colonialism and rebellion against it. The economy of Indonesia is the world's 16th-largest by nominal GDP and the 7th-largest by PPP. It is the world's third-largest democracy, a regional power, and is considered a middle power in global affairs.