Mainland Southeast Asia
Continental portion of Southeast Asia
From Wikipedia, the free encyclopedia
Mainland Southeast Asia (historically known as Indochina and the Indochinese Peninsula) is the continental portion of Southeast Asia. It lies east of the Indian subcontinent and south of Mainland China and is bordered by the Indian Ocean to the west and the Pacific Ocean to the east. It includes the countries of Cambodia, Laos, Myanmar, Thailand and Vietnam.[1]
The term Indochina (originally Indo-China) was coined in the early nineteenth century, emphasizing the historical cultural influence of Indian and Chinese civilizations on the region. The term was later adopted as the name of the colony of French Indochina (present-day Cambodia, Laos, and Vietnam). Today, the term "Mainland Southeast Asia" is more commonly used, in contrast to Maritime Southeast Asia for the island groups off the coast of the peninsula.
Terminology

A possible early name of mainland Southeast Asia was Suvarṇabhūmi ("land of gold"),[2] a toponym, that appears in many ancient Indian literary sources and Buddhist texts,[3] but which, along with Suvarṇadvīpa ("island" or "peninsula of gold"), are also thought to refer to insular Southeast Asia.
The origins of the name Indo-China are usually attributed jointly to the Danish-French geographer Conrad Malte-Brun, who referred to the area as indo-chinois in 1804, and the Scottish linguist John Leyden, who used the term Indo-Chinese to describe the area's inhabitants and their languages in 1808.[4] Scholarly opinions at the time regarding China's and India's historical influence over the area were conflicting, and the term was itself controversial—Malte-Brun himself later argued against its use in a later edition of his Universal Geography, reasoning that it overemphasized Chinese influence, and suggested Chin-India instead.[5] Nevertheless, Indo-China had already gained traction and soon supplanted alternative terms such as Further India and the Peninsula beyond the Ganges. Later, however, as the French established the colony of French Indochina (covering present-day Cambodia, Laos, and Vietnam), use of the term became more restricted to the French colony,[6] and today the area is usually referred to as Mainland Southeast Asia.[7]
Geography


The Indochinese Peninsula projects southward from the Asian continent proper. It contains several mountain ranges extending from the Tibetan Plateau in the north, interspersed with lowlands largely drained by three major river systems running in a north–south direction: the Irrawaddy (Myanmar), the Chao Phraya (in Thailand), and the Mekong (flowing through Northeastern Thailand, Laos, Cambodia and Vietnam). Most of it has a tropical climate except for subtropical places such as Northern Vietnam.[8]
Political divisions

Sovereign states
| State | Area (km2) |
Population (2025)[9] |
Density (/km2) |
HDI (2021)[10] |
Capital |
|---|---|---|---|---|---|
| 181,035[11] | 17,577,760 | 92 | 0.593 | Phnom Penh | |
| 236,800[12] | 7,647,000 | 31 | 0.607 | Vientiane | |
| 676,578[13] | 51,316,756 | 80 | 0.585 | Nay Pyi Taw | |
| 513,120[14] | 65,859,640 | 140 | 0.800 | Bangkok | |
| 331,210[15] | 101,343,800 | 294 | 0.703 | Hanoi |
Biogeography
Indochina is recognized as a distinct biogeographic region, part of the larger Indomalayan realm of tropical Asia.[16][17] Indochina is bounded on the north by temperate-climate China and the Tibetan Plateau, and on the northwest by the mountainous India-Myanmar border, and includes the tropical climate regions of Guangxi, Guangdong, Hainan, and Yunnan in southernmost China. The Indochina bioregion also includes the Andaman and Nicobar islands to the west, which are politically part of India. On the south it is bounded by the Kangar-Pattani Line, a biogeography boundary which bisects the Malay Peninsula near the Malaysia-Thailand border and separates the evergreen rain forests of Malesia, which receive year-round rainfall, from the seasonally dry tropical forests of Indochina.[16]
In the World Geographical Scheme for Recording Plant Distributions, Indo-China is a Level 2 subregion of Tropical Asia which includes Cambodia, Laos, Myanmar, Thailand, and Vietnam as well as the Andaman and Nicobar islands and the South China Sea Islands to the east, which are claimed by several neighboring countries. Peninsular Malaysia is part of the neighboring Level 2 Malesia region of Tropical Asia.[18]
Culture

Mainland Southeast Asia contrasts with Maritime Southeast Asia, mainly through the division of largely land-based lifestyles in Indochina and the sea-based lifestyles of the Indonesian archipelago and Philippine archipelago, as well as the dividing line between the Austroasiatic, Tai–Kadai, and Sino-Tibetan languages (spoken in Mainland Southeast Asia) and the Austronesian languages (spoken in Maritime Southeast Asia). The languages of the mainland form the Mainland Southeast Asia linguistic area: although belonging to several independent language families, they have converged over the course of history and share a number of typological similarities.[citation needed]
The countries of mainland Southeast Asia received cultural influence from both India and China to varying degrees.[19] Myanmar, Thailand, Laos, and Cambodia are all influenced by Indian culture. Vietnam is generally considered part of the Sinosphere, although it has also been influenced to a lesser extent by India.[citation needed]
Overall, Mainland Southeast Asia is religiously diverse, with Buddhism forming a majority religion in parts of the region, alongside minor Muslim,[20] Christian, and folk religious traditions.[citation needed]