Malaysia, country of Southeast Asia, lying just north of the Equator, that is composed of two noncontiguous regions: Peninsular Malaysia (Semenanjung Malaysia), also called West Malaysia (Malaysia Barat), which is on the Malay Peninsula, and East Malaysia (Malaysia Timur), which is on the island of Borneo. The Malaysian capital, Kuala Lumpur, lies in the western part of the peninsula, about 25 miles (40 km) from the coast; the administrative centre, Putrajaya, is located about 16 miles (25 km) south of the capital.
Malaysia, a member of the Commonwealth, represents the political marriage of territories that were formerly under British rule. When it was established on September 16, 1963, Malaysia comprised the territories of Malaya (now Peninsular Malaysia), the island of Singapore, and the colonies of Sarawak and Sabah in northern Borneo. In August 1965 Singapore seceded from the federation and became an independent republic.
Peninsular Malaysia occupies most of the southern segment of the Malay Peninsula. To the north it is bordered by Thailand, with which it shares a land boundary of some 300 miles (480 km). To the south, at the tip of the peninsula, is the island republic of Singapore, with which Malaysia is connected by a causeway and also by a separate bridge. To the southwest, across the Strait of Malacca, is the island of Sumatra in Indonesia. East Malaysia consists of the country’s two largest states, Sarawak and Sabah, and is separated from Peninsular Malaysia by some 400 miles (640 km) of the South China Sea. These two states occupy roughly the northern fourth of the large island of Borneo and share a land boundary with the Indonesian portion (Kalimantan) of the island to the south. Surrounded by Sarawak is a small coastal enclave containing the sultanate of Brunei. Of the country’s total area, which includes about 265 square miles (690 square km) of inland water, Peninsular Malaysia constitutes about 40 percent and East Malaysia about 60 percent.
The long, narrow, and rugged Malay Peninsula extends to the south and southwest from Myanmar and Thailand. The Malaysian portion of it is about 500 miles (800 km) long and—at its broadest east-west axis—about 200 miles (320 km) wide. About half of Peninsular Malaysia is covered by granite and other igneous rocks, one-third is covered by stratified rocks older than the granite, and the remainder is covered by alluvium. At least half the land area lies more than 500 feet (150 metres) above sea level.