The plateaus of North-East India constitute a vital sub-unit of the Peninsular Plateau system of India. Morphologically, these highlands are not part of the Himalayan mountain system but are detached structural extensions of the ancient Gondwanaland.
Tectonic Separation and the Malda Gap
The North-East plateaus, primarily represented by the Meghalaya (Shillong) Plateau and the Karbi Anglong Plateau of Assam, were originally contiguous with the Chota Nagpur Plateau. During the mid-Miocene Himalayan orogeny, the intense northward push of the Indian Plate created structural stresses. This resulted in the down-faulting of a massive block between the Rajmahal hills of Jharkhand and the Garo hills of Meghalaya. The resulting structural depression, known as the Rajmahal-Malda Gap (or simply the Malda Gap), was subsequently filled by the thick alluvial deposits of the Ganga and Brahmaputra river systems. This sedimentation isolated the North-East plateaus from the main Peninsular shield.
Structural Composition
The basement complex of these plateaus consists of Archaean gneisses, granites, and schists, overlain by younger Cretaceous and Tertiary sedimentary deposits of limestone and sandstone. The northern margins of these plateaus feature steep fault scarps overlooking the Brahmaputra Valley, while the southern slopes descend sharply into the Surma and Barak valleys of Bangladesh.
Major Regional Sub-Divisions
The Meghalaya (Shillong) Plateau
The Meghalaya Plateau is a highly dissected, tilted rectangular block sloping gently towards the north. Topographically, it is subdivided into three distinct hill groups from west to east, named after the indigenous tribes inhabiting them.
Garo Hills
Occupying the westernmost part of the plateau, the Garo Hills feature a highly denuded topography with lower average elevations. The highest peak in this segment is Nokrek Ridge, which functions as a critical biodiversity hotspot and gene sanctuary for citrus species.
Khasi Hills
Situated in the central portion, the Khasi Hills represent the most elevated and deeply dissected part of the plateau. The central upland forms a structural tableland characterized by rounded hills and deep gorges. Shillong Peak, the highest point of the entire plateau, is located here. The southern face of the Khasi Hills features massive limestone formations subjected to intense chemical weathering.
Jaintia Hills
Located in the eastern section of the Meghalaya Plateau, the Jaintia Hills form a contiguous upland with the Khasi Hills. This region is structurally rich in sedimentary deposits and is characterized by a rolling topography, extensive cave networks, and structural depressions.
The Karbi Anglong Plateau
The Karbi Anglong Plateau, located in Assam, is an eastern extension of the Meghalaya Plateau. It is separated from the Jaintia Hills by the Kopili River valley, a structural tract carved out by fluvial erosion.
Topographical Character
The Karbi Anglong Plateau exhibits an irregular shape and is deeply dissected by rivers like the Dhansiri, Jamuna, and Karbi. It features a mature topography with senile landforms, residual hills (monadnocks), and low undulating plains. It is broadly divided into two parts: the larger Western Karbi Anglong (Hamren sub-division) and the smaller Eastern Karbi Anglong.
Physiographic Profile and Key Peaks
The following table details the core geographical indicators, highest peaks, and structural alignments of the North-East plateau divisions:
| Plateau Sub-Division | Key Hill Ranges Included | Highest Peak & Elevation | Drainage System | Key Geological Characteristic |
| Western Meghalaya | Garo Hills | Nokrek Peak (1,412 meters) | Simsang and Nitai Rivers | Intensely weathered Archaean basement with thick soil profiles. |
| Central Meghalaya | Khasi Hills | Shillong Peak (1,961 meters) | Umiam, Umngot, and Digaru Rivers | Deeply incised V-shaped gorges; extensive tableland topography. |
| Eastern Meghalaya | Jaintia Hills | Marangksih Peak (1,631 meters) | Myntdu and Hari Rivers | Flat structural tops with extensive sedimentary sandstone beds. |
| Assam Extension | Karbi Anglong & North Cachar Hills | Singhason Peak (1,360 meters) | Dhansiri, Kopili, and Jamuna Rivers | Denuded ancient peneplain with prominent residual granitic domes. |
Hydrography, Weathering, and Karst Topography
Drainage Patterns
The North-East plateaus form a major drainage divide between the Brahmaputra Valley to the north and the Meghna (Barak-Surma) basin to the south. The northern rivers flow through narrow, steep gorges into the Brahmaputra, exhibiting high hydro-electric potential. The southern streams display a parallel drainage pattern, plunging down steep fault scarps via spectacular waterfalls like the Nohkalikai and Seven Sisters Falls.
Cherrapunji-Mawsynram Precipitation Mechanics
The southern margins of the Khasi Hills (specifically the Cherrapunji-Mawsynram orographic funnel) receive the highest annual rainfall in the world. The funnel-shaped alignment of the Garo, Khasi, and Jaintia hills forces the moisture-laden southwest monsoon winds blowing from the Bay of Bengal to ascend abruptly, leading to intense, continuous orographic precipitation.
Karst Landforms
Due to the presence of thick Tertiary Eocene limestone beds subjected to torrential rainfall, the southern slopes of the Meghalaya Plateau have developed world-class Karst topography. Acidic rainwater dissolves the calcium carbonate, creating extensive subterranean cave systems, sinkholes, blind valleys, stalactites, and stalagmites. Notable systems include Krem Liat Prah (India’s longest natural cave) and Krem Puri (the world’s longest sandstone cave).
Mineral Wealth and Economic Geography
The North-East plateaus are storehouses of high-grade mineral resources, historically extracted through both organized and unorganized traditional methods.
Coal Deposits
The plateau contains substantial reserves of sub-bituminous Tertiary coal, found predominantly in Bapung (Jaintia Hills), Langrin (Khasi Hills), and Daranggiri (Garo Hills). The coal has high sulfur content. Traditional extraction in these regions relies heavily on “rat-hole mining,” a hazardous primitive technique involving narrow horizontal tunnels dug into hill slopes.
Limestone and Sillimanite
High-grade flux-quality limestone is abundant along the southern belt, fueling major cement manufacturing clusters in Cherrapunji and Jaintia Hills. The Sonapahar region of the Khasi Hills historically held some of the world’s finest deposits of crystalline sillimanite (an industrial refractory mineral).
Uranium Reserves
The sandstone formations of Domiasiat and Wahkyn in the South Khasi Hills district contain some of the largest low-grade sandstone-type uranium deposits in India.
Geopolitics, Ecology, and Civilizational Trivia
Sixth Schedule Protections
Administratively, almost the entire North-East plateau region is covered under the Sixth Schedule of the Indian Constitution. Autonomous District Councils (ADCs)—such as the Garo Hills ADC, Khasi Hills ADC, Jaintia Hills ADC, and Karbi Anglong ADC—exercise decentralized legislative and executive powers to safeguard indigenous tribal customs, land tenure systems, and judicial processes.
Sacred Groves (Law Kyntang)
The Khasi and Jaintia tribes practice a traditional form of nature worship centered around sacred groves, locally termed Law Kyntang. These ecosystem fragments are strictly protected from timber extraction and hunting by customary religious laws. The Mawphlang Sacred Forest near Shillong serves as a prominent gene pool for ancient angiosperms, medicinal plants, and rare orchids.
Living Root Bridges (Jingkieng Jri)
In the Southern Khasi and Jaintia hills, indigenous communities train the aerial roots of the Ficus elastica (Indian Rubber Tree) across torrential rivers to form strong, self-healing, living pedestrian bridges. These bio-engineering marvels are uniquely adapted to withstand the extreme moisture and flash floods of the plateau’s southern slopes.
Nokrek Biosphere Reserve
Located in the Garo Hills, the Nokrek National Park is an internationally recognized UNESCO Biosphere Reserve. It is famous for conserving the Citrus indica (Indian Wild Orange), considered the mother progenitor of all cultivated citrus fruits globally. It also hosts a vital population of the endangered Red Panda and Hoolock Gibbon.
Last Modified: June 3, 2026