Strait of Johor in the context of "Peninsular Malaysia"

Peninsular Malaysia, historically known as Peninsular Malaya or simply Malaya prior to 1963, and also known as West Malaysia and the Malaysian Peninsula, is the southern part of the Malay Peninsula in Mainland Southeast Asia along with the nearby islands that are part of Malaysia. Its area totals approximately 131,956 km (50,948 sq mi). It makes up nearly 40% of the total area of Malaysia; the other 60% is on the island of Borneo, also known as East Malaysia.

The present-day land border with Thailand to the north originates from the Anglo–Siamese Treaty of 1909, while a maritime border with Singapore to the south was established following the independence of Singapore in 1965. To the west, across the Strait of Malacca, lies the island of Sumatra, and to the east, across the South China Sea, lie the Natuna Islands, both part of Indonesia. At its southern tip, across the Strait of Johor, lies the island country of Singapore. Most of Peninsular Malaysia's interior is forested, mountainous and rural, while the majority of the population and economic activity are concentrated along the coastal western half, where the country's major urban centres are located.