Purvanchal Range: Geography, Physiography, Hills, Climate and Natural Vegetation
The Purvanchal Range, also known as the Eastern Mountains, is an important mountain system of northeastern India. It represents the eastern extension of the Himalayan mountain system and forms a series of hills and ranges along India's international boundaries with Myanmar and, in the broader northeastern region, near Bangladesh and China.
The Purvanchal region is characterized by rugged hills, parallel mountain ranges, narrow valleys, plateaus, river systems and varying elevations. It covers important parts of Nagaland, Manipur, Mizoram and Tripura, along with adjoining hill regions of Assam and Arunachal Pradesh.
The Purvanchal Range is geographically significant because it forms a transition between the Eastern Himalaya, the northeastern hill region and the Arakan Yoma system.
Purvanchal Range at a Glance
| Feature | Description |
|---|---|
| Other name | Eastern Mountains |
| Location | Northeastern India |
| Origin | Eastern extension of the Himalayan mountain system |
| Major hill systems | Patkai Hills, Naga Hills, Manipur Hills, Mizo/Lushai Hills and Jampui Hills |
| Major geographical areas | Nagaland, Manipur, Mizoram, Tripura and adjoining northeastern hill regions |
| General relief | Rugged hills, parallel ranges and narrow valleys |
| Important valley | Imphal Valley |
| Highest peak mentioned | Dapha Bum – 4,579 m |
| Important peak in Naga Hills | Saramati – 3,926 m |
| Important river system | Drainage toward both Indian and Myanmar river systems |
Location and Geographical Setting of the Purvanchal Range
The name Purvanchal refers to the eastern mountainous region of India. The region occupies the eastern part of Northeast India and extends along the country's international frontier with Myanmar.
Its northwestern boundary is associated with the Meghalaya-Mikir region, Assam Valley and Eastern Himalaya, while the plains of Tripura and Cachar form important transitional areas toward the Surma Valley.
The Purvanchal landscape is therefore characterized by a combination of:
Mountain ranges
Narrow valleys
Hill slopes
River valleys
Forests
Plateaus
Intermontane basins
Low-lying plains
Its geographical position makes the region an important physical and cultural transition zone between the Himalayas, the plains of Assam and the mountain systems extending toward Myanmar.
Geography of Purvanchal Range
According to the source material, the Purvanchal Range covers an area of approximately 94,800 square kilometres and extends over a considerable part of northeastern India.
The range has an approximate north-south length of 755 km and a maximum east-west width of about 615 km.
The Purvanchal Range is considered an eastern extension of the Himalayan mountain system. Beyond the Dihang River gorge, the Himalayan ranges bend sharply toward the south and continue along the eastern frontier of India toward Myanmar.
This mountain system eventually connects with the broader Arakan Yoma mountain system.
Major Hills and Ranges of Purvanchal
The Purvanchal Range consists of several important hill systems. The major ones include:
Patkai Hills
Naga Hills
Manipur Hills
Mizo or Lushai Hills
Jampui Hills
These ranges differ considerably in elevation, slope, geological structure, vegetation and valley formation.
1. Patkai Hills
The Patkai Hills are located along the northeastern frontier of India and form an important part of the Purvanchal mountain system.
The Patkai landscape is characterized by:
Conical peaks
Steep slopes
Deep valleys
Dense forests
Sandstone formations
Rugged terrain
The Patkai region forms an important geographical divide and contributes to the drainage systems of northeastern India and Myanmar.
The name Patkai is traditionally associated with the Tai-Ahom language. The range is part of the larger mountain system that developed through geological processes associated with the Himalayan and Indo-Myanmar mountain systems.
2. Naga Hills
The Naga Hills extend through Nagaland and continue into Myanmar. They form one of the major components of the Purvanchal Range.
The Naga Hills are characterized by:
High mountain ridges
Deep valleys
Steep slopes
Dense forests
Narrow river valleys
The eastern frontier of Nagaland acts as an important watershed between drainage systems flowing toward India and Myanmar.
One of the most important peaks of the Naga Hills is Mount Saramati, which rises to approximately 3,926 metres.
The Tizu River system provides an important example of drainage crossing the mountain region toward Myanmar.
3. Manipur Hills
The Manipur Hills surround the central Imphal Valley and form a distinctive geographical landscape.
The hills form an approximately oval-shaped rim around the valley, creating an enclosed intermontane basin.
The Imphal Valley is an important physical feature of Manipur. The valley contains relatively low-lying terrain surrounded by higher hills, while Loktak Lake occupies an important position within the valley system.
The surrounding hills influence:
Climate
Drainage
Agriculture
Settlement
Transportation
Natural vegetation
The contrast between the enclosed Imphal Valley and the surrounding hills is one of the distinctive physiographic characteristics of the Purvanchal region.
4. Mizo Hills or Lushai Hills
The Mizo Hills, formerly known as the Lushai Hills, occupy much of Mizoram and form an important southern section of the Purvanchal Range.
They are characterized by a remarkable arrangement of:
Parallel ridges
Narrow valleys
Steep slopes
Forested hills
Long north-south-oriented ranges
The Mizo Hills are connected with the broader mountain system extending toward the Arakan Yoma.
Most of the area has elevations between approximately 150 and 900 metres, although higher peaks exceeding 1,500 metres occur in the region.
The parallel arrangement of ridges and valleys strongly influences settlement, transportation, agriculture and drainage in Mizoram.
5. Tripura Hills and Jampui Hills
The Tripura Hills, including the Jampui Hills, form the southwestern part of the Purvanchal hill system.
The hills generally consist of parallel north-south-oriented ridges. Their elevation gradually decreases toward the south and west, where the hills merge into the surrounding plains.
Important hill ranges include:
Deotamura Range
Atharamura Range
Langtarai Range
Jampui Hills
Sakhan Tlang
The Tripura-Cachar region represents an important transition between the hill systems and the low-lying plains.
Physiography of the Purvanchal Range
The physiography of the Purvanchal Range is dominated by parallel mountain ranges, narrow valleys, steep slopes and varying elevations.
The mountain ranges generally run in a north-south or northeast-southwest direction. Between these ranges are narrow valleys through which rivers and streams flow.
The region becomes increasingly mountainous toward the northeast. Elevation varies considerably across relatively short distances, producing substantial differences in climate and vegetation.
Altitudinal Variation
The Purvanchal region has considerable variation in elevation.
Except for the plains of Tripura and Cachar, much of the region remains above approximately 150 metres.
The Mizo Hills largely occupy the 150–900 metre elevation zone, although peaks above 1,500 metres also occur.
Large portions of the Manipur Hills and Nagaland occur between approximately 900 and 2,100 metres.
This altitudinal variation creates different ecological zones and contributes to the region's rich biodiversity.
Dapha Bum: A High Mountain of the Purvanchal Region
Dapha Bum is identified in the source material as the highest range in the region, reaching an elevation of approximately 4,579 metres.
It is located in the Arunachal Pradesh sector and is characterized by highly dissected terrain.
Numerous rivulets and streams cut through the mountain slopes, producing a rugged landscape with deep valleys and steep slopes.
The high elevation of this part of the Purvanchal region also produces climatic and vegetation conditions different from those of the lower hills.
Barail Range and Nagaland Hills
The Barail Range extends from the southwest through North Cachar toward Nagaland and reaches the Kohima region.
An important peak mentioned in the source is Japavo, with an elevation of approximately 2,970 metres.
Further east are the Kohima Hills and Naga Range, where elevations increase substantially.
The eastern mountain frontier is also significant from a drainage perspective because it forms a watershed between rivers flowing toward India and Myanmar.
Imphal Valley: An Important Physiographic Feature
The Imphal Valley is one of the most distinctive physical features of the Purvanchal region.
It is surrounded by the hills of Manipur, which form an approximately oval-shaped enclosure around the valley.
The valley can be visualized as an elongated, shallow basin surrounded by mountains. Loktak Lake occupies an important low-lying portion of the valley.
The physical structure of the Imphal Valley has influenced the concentration of:
Agriculture
Population
Transport
Urban settlements
Wetlands
Economic activities
The surrounding hills provide a dramatic contrast to the relatively level valley floor.
Drainage of the Purvanchal Range
The complex relief of the Purvanchal Range has produced an equally complex drainage system.
Mountain ridges act as watersheds, while rivers flow through narrow valleys and deeply dissected terrain.
The eastern frontier of Nagaland forms a major drainage divide between rivers flowing toward the Indian side and those entering Myanmar.
The steep slopes of the mountain ranges also encourage rapid runoff during the monsoon season.
Consequently, rivers in the hill regions can experience sudden increases in discharge during periods of heavy rainfall.
Climate of Purvanchal Range
The Purvanchal region experiences a predominantly monsoonal climate, although temperature and rainfall vary considerably because of differences in elevation, latitude and relief.
The region has a strong seasonal rhythm, with four broad seasons:
Winter
Pre-monsoon
Southwest Monsoon
Retreating Monsoon
The rugged topography causes considerable local variations in temperature and rainfall. Higher elevations generally experience cooler conditions, while the lower valleys and plains have warmer and more humid conditions.
Winter Season: December to February
Winter begins with a marked decrease in temperature. January is generally the coldest month.
Temperatures begin to rise gradually toward February as the region transitions toward the pre-monsoon season.
Higher mountain areas experience considerably cooler conditions than the surrounding lowlands.
Pre-Monsoon Season: March to April
The pre-monsoon season begins with a rapid increase in temperature.
As the season progresses, rainfall becomes more frequent. Convective thunderstorms and local rainfall become increasingly important before the arrival of the southwest monsoon.
Monsoon Season: May to September
The monsoon season is the dominant rainy period.
The increase in temperature characteristic of the pre-monsoon period is moderated by persistent rainfall and cloud cover.
The source identifies June as the wettest month, followed by July and May.
Heavy rainfall is particularly important in the hill regions because steep slopes can accelerate runoff and contribute to soil erosion and landslides.
Retreating Monsoon: October to November
Toward the end of September, the southwest monsoon gradually weakens.
During October and November, rainfall decreases, skies become clearer and temperatures gradually decline.
This period generally provides more comfortable weather conditions before the onset of winter.
Natural Vegetation of Purvanchal Range
The Purvanchal Range is one of the important forest regions of northeastern India.
Its rich natural vegetation is closely related to variations in:
Altitude
Latitude
Climate
Soil
Rainfall
Slope
These environmental variations support different forest types ranging from tropical evergreen forests to temperate evergreen and coniferous vegetation.
The region's forests also support considerable biodiversity and provide important ecological services such as soil conservation, water regulation and habitat protection.
Tropical Evergreen Vegetation
Tropical evergreen vegetation occurs mainly in the warmer and wetter parts of the region.
Plants mentioned in the source include:
Mesua ferrea
Careya arborea
Ficus elastica
Photiki
Photkola
Dense bamboo vegetation is also widespread in many parts of the Purvanchal region.
The warm and humid climate of the lower hills supports dense vegetation, particularly in areas receiving abundant rainfall.
Temperate Evergreen Vegetation
At higher elevations, the vegetation changes in response to lower temperatures.
Important trees associated with temperate evergreen forests include:
Oak
Chestnut
Birch
Mongolian oak
Cherry
Maple
Laurel
Fig
These forests demonstrate the strong relationship between altitude and vegetation in the Purvanchal mountains.
Bamboo Forests of Purvanchal
Bamboo is one of the most widespread plant resources of the northeastern hill region.
Bamboo grows extensively across the Purvanchal landscape and has both ecological and economic importance.
It contributes to:
Soil conservation
Rural livelihoods
Traditional construction
Handicrafts
Furniture
Cultural practices
However, changes in land use and traditional shifting cultivation can influence forest structure and regeneration.
Jhum Cultivation and Forests
The natural vegetation of the Purvanchal region has historically been influenced by Jhum cultivation, also known as shifting cultivation.
The source notes that centuries of Jhum practices have affected forest vegetation in the region.
The environmental impact of shifting cultivation varies according to fallow periods, population pressure, slope, rainfall and land-management practices.
Where fallow periods become shorter, soil fertility and forest regeneration can be affected. Sustainable land management and improved agricultural practices are therefore important for maintaining the ecological health of the hill regions.
Importance of the Purvanchal Range
The Purvanchal Range is important from geographical, ecological, economic and strategic perspectives.
1. Geographical Importance
It forms the eastern extension of the Himalayan mountain system and connects the Eastern Himalaya with the mountain systems toward Myanmar.
2. Ecological Importance
The variation in elevation, rainfall and climate supports diverse forest ecosystems and wildlife habitats.
3. River and Watershed Importance
The mountain ranges act as watersheds and give rise to numerous rivers and streams.
4. Cultural Importance
The hills are home to diverse communities with distinctive cultures, traditions and land-use practices.
5. Agricultural Importance
Valleys and lower slopes provide areas for settled cultivation, while traditional agricultural systems have developed in the hill regions.
6. Strategic Importance
The Purvanchal mountain system lies along India's international frontier with Myanmar and forms an important geographical component of India's northeastern border region.
Conclusion
The Purvanchal Range, or Eastern Mountains, is a major physiographic system of Northeast India and represents an important eastern extension of the Himalayan mountain system.
Its landscape is dominated by parallel mountain ranges, steep slopes, narrow valleys and considerable altitudinal variation. The principal hill systems include the Patkai Hills, Naga Hills, Manipur Hills, Mizo or Lushai Hills and Jampui Hills.
The region's varied relief strongly influences its climate, drainage, natural vegetation, agriculture, settlement and biodiversity. From the high mountains of Arunachal Pradesh to the parallel ridges of Mizoram and the hills surrounding the Imphal Valley, the Purvanchal Range displays remarkable physical diversity.
Understanding the geography and physiography of the Purvanchal Range is essential for understanding the physical geography of Northeast India and the relationship between the Eastern Himalaya, northeastern hill states and the mountain systems of Myanmar.
Frequently Asked Questions (FAQ)
What is the Purvanchal Range?
The Purvanchal Range, also called the Eastern Mountains, is an eastern extension of the Himalayan mountain system in northeastern India.
Which are the major hills of the Purvanchal Range?
The major hill systems are the Patkai Hills, Naga Hills, Manipur Hills, Mizo or Lushai Hills and Jampui Hills.
Where is the Purvanchal Range located?
The Purvanchal Range is located in Northeast India, extending through important parts of Nagaland, Manipur, Mizoram and Tripura, along with adjoining hill regions of Assam and Arunachal Pradesh.
What is the highest peak mentioned in the Purvanchal region?
The source identifies Dapha Bum, with an elevation of approximately 4,579 metres, as the highest range in the region.
What is the highest peak of the Naga Hills?
Saramati, at approximately 3,926 metres, is identified in the source as the highest peak of the Naga Hills.
What are the main physiographic features of the Purvanchal Range?
The main features include parallel mountain ranges, steep slopes, narrow valleys, intermontane basins, forested hills and varying elevations.
What is the Imphal Valley?
The Imphal Valley is an important intermontane valley surrounded by the hills of Manipur. Loktak Lake occupies an important low-lying area within the valley.
What type of climate does the Purvanchal Range have?
The region has a predominantly monsoonal climate, with significant variations caused by altitude, latitude and relief.
What type of vegetation is found in the Purvanchal Range?
Vegetation ranges from tropical evergreen forests at lower elevations to temperate evergreen and coniferous vegetation at higher elevations.
Why is the Purvanchal Range important?
The Purvanchal Range is important for its mountain ecosystems, biodiversity, watersheds, forests, agriculture, cultural diversity and strategic location in Northeast India.