Malaysia is the only Southeast Asian country that is part of both mainland and archipelagic Asia. The mainland peninsula is the country’s heartland. Roughly conical in shape, Peninsular Malaysia is about 450 miles (720 km) long, narrowing from a maximum width of 200 miles (320 km) to 60 miles (95 km) at its southern tip. Its area of 50,806 square miles (131,587 sq km), including Pinang and other nearby small islands, accounts for 40% of the nation’s territory. A rail and road causeway spans Johor Strait in the south, joining Peninsular Malaysia with the island republic of Singapore.
About 400 miles (640 km) to the east, across the South China Sea, are the Borneo coastal states of Sarawak and Sabah. They and independent Brunei occupy the northern third of the island of Borneo, the rest of which is part of Indonesia. Sarawak has an area of 48,050 square miles (124,449 sq km), or 38% of the national territory. Sabah, formerly North Borneo, covers 28,461 square miles (73,713 sq km), or 22% of the nation’s area.
The Malay Peninsula and Borneo are elevated portions of the partially submerged Sunda Platform, which extends from the mainland into insular Southeast Asia. The peninsula is marked in its northern half by parallel series of short, geologically old mountain ranges. To the south, elevations diminish to hilly ridges and finally flatten in the deep south into the Johor Lowlands. The generally hilly peninsular terrain is indented by flat, often swampy alluvial plains that extend 5 to 40 miles (865 km) inland.
The terrain of the Borneo states is similar. Alluvial, swampy coastal plains change inland to hilly country and then to mature mountain ranges. Mount Kinabalu (13,455 feet, or 4,101 meters), in Sabah, is Malaysia’s highest peak.
Malaysia’s flora forms a greater obstacle to human habitation and communication than does topography. Tropical rain forest, or jungle, covers 70% of the nation’s terrain. Water has had an immense influence on life in Malaysia. Most of the people live in settlements near rivers or the sea. In some places the rivers provide the only practical means for moving through the jungle. Rivers on the peninsula are short and run in a general north-south direction. Rivers in Sarawak and Sabah flow northeast or west to the Sulu or South China seas. Approximately one third of the 350-mile (560-km) course of the Rajang River in Sarawak is navigable. The Kinabatangan River is the most important waterway in Sabah.
Malaysia’s climate is tropical and monotonously uniform. The temperature averages 80° F (27° C), relative humidity 80%90%, and annual rainfall 100 inches (2,540 mm). There is scarcely enough fluctuation in rainfall and wind direction to produce seasonal changes.
Malaysian soils are low in inherent fertility, except in coastal alluvial areas, but the country has the proper climate and drainage for rubber trees to grow in its poor soils. Pineapples thrive on Malaysia’s peat, which is formed mostly by rotting wood and water. The rain forests include valuable stands of tropical hardwoods. Mineral resources are moderate. Tin and petroleum are of major importance, but coal and iron ore for industrial development are not abundant.