Peninsular Malaysia (Malay: Semenanjung Malaysia), also known as West Malaysia (formerly Malaya), is the part of Malaysia which lies on the Malay Peninsula. Its area is 131,598 square kilometers (50,810 sq mi). It shares a land border with Thailand in the north. To the south is the island of Singapore. Across the Strait of Malacca to the west lies the island of Sumatra. East Malaysia (on the island of Borneo) is to the east across the South China Sea. With an estimated population of 21 million, it accounts for the majority (roughly 80%) of Malaysia's population and economy.