Singapore, Republic of, independent city-state in South East Asia, comprising one major island and 59 small adjacent islets, located off the southern tip of the Malay Peninsula. Singapore Island, the major island, is separated from Malaysia to the north by the narrow Johor Strait. On the south, it is separated from the Riau archipelago of Indonesia by Singapore Strait, an valuable shipping channel linking the Indian Ocean to the west with the South China Sea on the east. The city of Singapore is at the south-eastern end of the island; it is one of the most valuable port cities and commercial centres of South East Asia. The total area of the republic is 640 sq km (247 sq mi).