Indonesia is the world's fourth most populous country in the world after China, India, and the United States. Estimated population up to April 2007 is 248,287,819, giving it an average population density of 123 persons per sq km (319 per sq mi). More than half the people live on Java, where Jakarta, Indonesia's capital and largest city, is located. It homes more than 491 ethnic groups, speak more 567 different languages or dialects.
Followers of Islam make up 87 percent of the population, making Indonesia the most populous Muslim-majority nation in the world. Christians represent 9 percent of the population. Most of these belong to the Protestant Church in Indonesia, a merger of several Protestant sects. There are also many other locally organized Protestant groups, such as the Batak Protestant Christian Church, which claims about 2 million members. About 2 percent of the population is Roman Catholic. Buddhists, most of whom are of Chinese descent, account for about 1 percent of the population. Hinduism was once a major influence throughout the region but is now significant only on Bali.
Indonesia is located south and east of mainland Asia and north and west of Australia. About half of Indonesia's of more than 17,000 islands are inhabited; all are located in the Indian and Pacific oceans. This makes Indonesia the largest archipelagic country in the world.
Indonesia is surrounded by the South China Sea, the Celebes Sea, and the Pacific Ocean to the north, and by the Indian Ocean to the south and west.