Indonesia,^[a] officially the Republic of Indonesia,^[b] is a transcontinental country spanning the southeastern part of Asia and western part of 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 275 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.

Indonesia is a presidential republic with an elected legislature. It has 38 provinces, of which nine have special status. The country's capital, Jakarta, is the world's second-most populous urban area. Indonesia shares land borders with Papua New Guinea, East Timor, and the eastern part of Malaysia, as well as maritime borders with Singapore, Vietnam, Thailand, the Philippines, Australia, Palau, and India (Andaman and Nicobar Islands). 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.