The Strait of Malacca is a narrow stretch of water, 500 mi long and from 40 to 155 mi wide, between the Malay Peninsula to the northeast and the Indonesian island of Sumatra to the southwest, connecting the Andaman Sea and the South China Sea. As the main shipping channel between the Indian and Pacific oceans, it is one of the most important shipping lanes in the world. It is named after the Malacca Sultanate that ruled over the strait between 1400 and 1511, the center of administration of which was located in the modern-day state of Malacca, Malaysia.

Peninsular Malaysia, historically known as Malaya, also known as West Malaysia or the "Malaysian Peninsula", is the western part of Malaysia that comprises the southern part of the Malay Peninsula on Mainland Southeast Asia and the nearby islands. Its area totals approximately 132,490 km2 (51,150 sq mi), which is nearly 40% of the total area of the country; the other 60% is in East Malaysia on the island of Borneo.