Southeast Asia

Southeast Asia is the geographical southeastern region of Asia, consisting of the regions that are situated south of China, east of the Indian subcontinent, and northwest of mainland Australia, which is a part of Oceania. Southeast Asia is bordered to the north by East Asia, to the west by South Asia and the Bay of Bengal, to the east by Oceania and the Pacific Ocean, and to the south by Australia and the Indian Ocean. Apart from the British Indian Ocean Territory and two out of 26 atolls of the Maldives in South Asia, Maritime Southeast Asia is the only other subregion of Asia that lies partly within the Southern Hemisphere. Mainland Southeast Asia is entirely in the Northern Hemisphere. Timor-Leste and the southern portion of Indonesia are the parts of Southeast Asia that are located south of the equator.

The region lies near the intersection of geological plates, with both heavy seismic and volcanic activities. The Sunda plate is the main plate of the region, featuring almost all Southeast Asian countries except Myanmar, northern Thailand, northern Laos, northern Vietnam, and northern Luzon of the Philippines, while the Sunda plate only includes western Indonesia to as far east as the Indonesian province of Bali. The mountain ranges in Myanmar, Thailand, Peninsular Malaysia, and the Indonesian islands of Sumatra, Java, Bali, Lesser Sunda Islands, and Timor are part of the Alpide belt, while the islands of the Philippines and Indonesia as well as Timor-Leste are part of the Pacific Ring of Fire. Both seismic belts meet in Indonesia, causing the region to have relatively high occurrences of earthquakes and volcanic eruptions, particularly in the Philippines and Indonesia.

It covers about 4,500,000 km2 (1,700,000 sq mi), which is 9.80% of Asia, 8% of Eurasia and 3% of Earth's total land area.