Indonesia, officially the Republic of Indonesia (Indonesian: Republik Indonesia), is a nation of islands consisting of almost 18,000 islands located in the South East Asian Archipelago. Jakarta, formerly known as Batavia, is Indonesia's capital. Indonesia (from Greek: indus = India nesos = islands) is the world's largest archipelagic nation, bordered by the nations of Papua New Guinea, East Timor, and Malaysia. With a population of over 200 million, it is the world's fourth most populous country and most populous Muslim-majority nation.

The area now comprising the archipelago of Indonesia, specifically Java, was inhabited by Homo erectus - the Java Man - approximately 500,000 years ago, while the island of Flores was home to what may be a newly discovered species of hominid, Homo floresiensis. The region was an important trade route to China, thriving in trade of spices. Regional Hindu kingdoms expanded religious and cultural influences of Hinduism as well as Buddhism, and in the Middle Ages, the islands came under the influence of Islam. The region was colonized by the Netherlands as the Dutch East Indies. The people across many islands rebelled in the early 20th century against Dutch control. Following a brief occupation by Imperial Japan during World War II, nationalists declared independence in 1945, and a united and independent Indonesia was recognized in 1949. It was also recognized by the UN in 1953.

Indonesia is a unitary state, and was governed by Sukarno, leader of the national freedom struggle, and military dictator Suharto for most of its modern history. Democracy was restored following the revolution of 1998. Although the national language is Indonesian (called Bahasa Indonesia in Indonesian) and the population is overwhelmingly Muslim, there are several hundred diverse linguistic and ethnic groups across the country, as well as other religious communities. Although Indonesia's economy is progressive and regionally important, the problems of poverty, illiteracy, political instability and regional separatism remain major issues hindering national development.