West Bengal

Geography

West Bengal covers 88,752 km² between 21°25′ N and 27°13′ N. North-south extent is approximately 600 km. The conventional physiographic division of the state separates the Himalayan north, the Terai-Dooars piedmont and the Gangetic deltaic plain. Bandyopadhyay et al. (2015) subdivide the state into nine geomorphological zones: the Darjeeling Himalaya, sub-Himalayan alluvial fans, the Barind uplands, the degenerated Chhotanagpur plateau fringe, the lateritic Rarh, the upper Ganga delta, the reclaimed lower delta, the non-reclaimed mangrove Sundarbans and the Medinipur coastal plain. Elevations range from sea level in the Sundarbans to 3,636 m at Sandakphu on the Singalila Ridge.

Physiography

The Darjeeling Himalaya occupies about one per cent of the state's area but contains its highest relief. Phyllites and schists predominate around Kalimpong. Gneiss dominates around Darjeeling. The rocks have been intensely sheared by the underthrusting of the Indian plate, producing slope instability and landslide hazard across the hill districts. The Singalila Ridge on the India-Nepal boundary carries Sandakphu (3,636 m), the highest point in West Bengal, and Phalut (3,600 m). The Teesta gorge separates the Singalila and Darjeeling ranges to the west from the lower hills around Kalimpong to the east.

South of the Himalayan front a belt of Bhabar (gravel and boulder fans) and Terai (clay and sand alluvium with a high water table) grades into the Dooars piedmont. The Dooars proper lies between 90 m and 1,750 m elevation across Jalpaiguri, Alipurduar and the northern margin of Cooch Behar.

The Rarh region of the southwest (Purulia, Bankura, Birbhum, parts of Paschim Bardhaman and Paschim Medinipur) is an undulating laterite-capped erosional surface continuous with the Chota Nagpur plateau. The Bhagirathi separates Rarh to the west from Bagri to the east in Murshidabad. The Sundarbans form a tidally active distal delta of the Ganga-Brahmaputra-Meghna system, simultaneously prograding and eroding. Surface elevations range from 0.5 m to 3 m, with about seventy per cent of the area below 1 m.

Climate

Köppen-Geiger classifications follow the relief of the state. The Darjeeling and Kalimpong hills are subtropical highland (Cwb). Most of the western and northern plains are humid subtropical (Cwa). Kolkata, Haldia and the deltaic south are tropical wet-and-dry (Aw). The India Meteorological Department treats the state under two meteorological subdivisions: Gangetic West Bengal and Sub-Himalayan West Bengal and Sikkim.

Four seasons are recognised: winter (December to February), pre-monsoon (March to May, with Kalbaishakhi or Nor'wester thunderstorms in the south), the southwest monsoon (June to September) and the retreating or post-monsoon (October to November). The Bay of Bengal supplies the moisture. The Himalaya force orographic uplift. Rainfall therefore increases northward and into the foothills. Seventy-five to eighty per cent of annual rainfall falls during the southwest monsoon. Tropical cyclones including Aila (2009), Amphan (2020) and Yaas (2021) periodically affect the deltaic and coastal districts.

Representative climate stations

Station	Köppen	Mean annual temperature (°C)	Mean annual rainfall (mm)
Darjeeling (2,042 m)	Cwb	14.9	3,100
Jalpaiguri (Dooars)	Cwa	24.5	3,200
Kolkata (Alipore)	Aw	26.7	1,711.5
Malda	Cwa	25.4	1,349
Asansol (Rarh)	Cwa	25.3	1,294
Haldia (coast)	Aw	26.2	1,654

Long-term records at Darjeeling indicate a mean annual temperature increase of about 4 °C since the late nineteenth century, with a concurrent decline in annual rainfall.

Rivers and hydrology

Three drainage systems converge in West Bengal. Himalayan rivers (the Teesta, Jaldhaka, Torsa, Raidak, Sankosh and Mahananda) drain North Bengal and ultimately the Brahmaputra. The Ganga-Padma-Bhagirathi/Hooghly system dominates central and southern Bengal. At the Farakka Barrage the river splits into the Padma (which crosses into Bangladesh) and the Bhagirathi-Hooghly (which carries the southward flow to the Bay of Bengal through Kolkata and Haldia). Peninsular rivers originating in the Chota Nagpur plateau (the Damodar, Ajay, Mayurakshi, Rupnarayan and Kangsabati) drain the Rarh.

Major river basins

River	Source	Length (total / within WB)	Catchment	Notes
Ganga-Padma	Gangotri Glacier, Uttarakhand	2,575 km / 570 km	74,732 km² in WB (Ganga system)	Splits at Farakka into Padma and Bhagirathi-Hooghly
Bhagirathi-Hooghly	Distributary of Ganga at Farakka	520 km		Industrial corridor and Kolkata port
Teesta	Pahunri and Tso Lhamo, Sikkim	414 km / 142 km	12,159 km² total	Largest North Bengal river; principal tributary is the Rangit
Jaldhaka	Bitang Lake, Sikkim	233 km	4,092 km² (to Mathabhanga)	Trans-boundary across India, Bhutan and Bangladesh
Torsa	Chumbi Valley, Tibet	358 km + 99 km in WB	7,486 km²	Drains Cooch Behar
Raidak	Bhutan	50 km in WB	4,852 km²	Joins the Brahmaputra system
Mahananda	Paglajhora Falls, Darjeeling (2,100 m)	360 km (324 in India)	20,600 km² (11,530 in India)	Tributaries include the Balason, Mechi and Kankai
Damodar	Palamau hills, Jharkhand	592 km	25,820 km² (8.6 per cent in WB)	Regulated by the Damodar Valley Corporation (Maithon, Panchet, Konar and Tilaiya dams)

The combined catchment of the five major North Bengal rivers (Teesta, Torsa, Jaldhaka, Raidak and Sankosh) within West Bengal is 37,545 km². The Sundarbans tidal network (the Hooghly, Matla, Bidyadhari, Raimangal, Ichhamati and Saptamukhi distributaries with their creeks) covers about 4,260 km² in India, of which 1,700 km² is open water.

The Padma-Ganga and lower Bhagirathi floodplains, with their light well-drained silt-renewed alluvial loams, supplied the agronomic foundation of the historical Bengal ganja economy across both banks of what is now the international border. The Indian portion of this belt lies in Murshidabad, Malda, Nadia and the northern fringe of North 24 Parganas (see History below).

Soils

The state's soil cover, classified by the Indian Council of Agricultural Research's National Bureau of Soil Survey and Land Use Planning, comprises six broad families.

• Gangetic (new) alluvium. Neutral to mildly alkaline (pH 7.0–8.2), deep, fertile and high in water-holding capacity. Underlies Murshidabad, Nadia, Hooghly, the Bardhaman districts, North 24 Parganas and much of South 24 Parganas. About 3.5 million hectares of alluvial soils statewide.
• Vindhya (old) alluvium. Derived from Rajmahal and Chotanagpur drainage; mildly acidic (pH 6.0–6.6). Parts of Murshidabad, Birbhum and Purba Bardhaman.
• Lateritic and red soils. Coarse, well-drained, ferruginous and acidic (pH 5.5–6.9), low in organic matter. Purulia, Bankura, Birbhum, parts of Paschim Bardhaman and Paschim Medinipur. The Rarh soil regime.
• Terai and Bhabar soils. Darjeeling foothills, Jalpaiguri, Alipurduar and Cooch Behar. Acidic (pH 6.0–6.6), nutrient-poor on the higher fans. Support tea on the better-drained slopes.
• Coastal saline and alkaline soils. South 24 Parganas (Sundarbans), parts of Howrah and Purba Medinipur. Calcium- and magnesium-rich with decomposed organic matter. Salinity from tidal inundation.
• Mountain (skeletal and colluvial) soils. Darjeeling and Kalimpong. Thin and well-drained, supporting tea on the lower flanks and temperate-forest soils above.

Ecology and forests

West Bengal lies at the junction of three biogeographic provinces: the Eastern Himalaya (a global biodiversity hotspot), the Indo-Gangetic plain and the Deccan Peninsular (via the Chota Nagpur plateau). Four principal forest types are mapped under the Champion and Seth classification:

1. Tropical moist and dry deciduous Sal forests of the Dooars and Terai. Shorea robusta with Tectona grandis, Bombax ceiba and Lagerstroemia. The Mahananda, Gorumara, Jaldapara, Buxa and Chapramari protected areas lie within this belt.
2. Tropical dry deciduous and sal coppice of the plateau fringe. Medinipur, Bankura, Purulia, the Bardhaman districts and Birbhum. Dominated by sal with Butea monosperma, Madhuca longifolia and Diospyros melanoxylon. The Jhargram, Garhbeta and Ayodhya Hill ecosystems fall here.
3. Tidal mangrove forests of the Sundarbans. Heritiera fomes (sundari), Excoecaria agallocha (gewa), Avicennia spp., Ceriops decandra (goran) and Phoenix paludosa (hantal). The Sundarban Biosphere Reserve covers 9,630 km² in India and contains the Sundarban Tiger Reserve, Sajnekhali, Lothian and Halliday Island sanctuaries.
4. Subtropical broadleaf and temperate forests of the Darjeeling-Kalimpong hills. Quercus, Castanopsis, Michelia, Rhododendron, Magnolia and Tsuga dumosa. The Singalila and Neora Valley National Parks protect the highest reaches.

Recorded forest cover totals 16,901.51 km², or 19.04 per cent of the state's geographic area. The Sundarbans hold about 2,114 km² of dense mangrove forest, the largest single block in India and (combined with the Bangladeshi portion of the same delta) the largest contiguous mangrove forest in the world. Two tiger reserves operate in the state: the Sundarban Tiger Reserve (3,629.57 km², the second-largest tiger reserve in India following the August 2025 area expansion approved by the National Board for Wildlife) and the Buxa Tiger Reserve in the Dooars. Three communities are notified as Particularly Vulnerable Tribal Groups (PVTGs): the Toto, the Birhor and the Lodha.

Administrative geography

West Bengal is administered through five divisions (Presidency, Burdwan, Medinipur, Malda and Jalpaiguri) comprising twenty-three districts as of 1 November 2023. Each division corresponds approximately to a coherent physiographic region: Presidency to the lower deltaic plain; Burdwan to the Rarh and Damodar valley; Medinipur to the southwestern plateau-fringe and coastal plain; Malda to the middle Gangetic plain and Barind uplands; and Jalpaiguri to the sub-Himalayan plains, the Dooars and the Darjeeling Himalaya. In August 2022 the state cabinet approved in principle the creation of seven additional districts (Ichhamati, Basirhat, Sundarban, Bishnupur, Jangipur, Berhampore and Ranaghat), which would raise the total to thirty. These had not been formally constituted as of late 2025.

Districts of West Bengal (selected statistics; population 2011 Census unless noted)

District	Division	Area (km²)	Population	Predominant zone
Darjeeling	Jalpaiguri	3,149	1,846,823	Himalayan / Hill
Kalimpong	Jalpaiguri	1,044	251,642	Himalayan / Hill
Jalpaiguri	Jalpaiguri	3,386	3,872,846	Dooars / Terai
Alipurduar	Jalpaiguri	3,383	1,491,250	Dooars / Terai
Cooch Behar	Jalpaiguri	3,387	2,819,086	Terai / north plain
Uttar Dinajpur	Malda	3,140	3,007,134	North alluvial plain
Dakshin Dinajpur	Malda	2,219	1,676,276	Barind / north plain
Malda	Malda	3,733	3,988,845	Gangetic plain / Barind
Murshidabad	Presidency	5,324	7,103,807	Gangetic plain (Bagri / Rarh)
Nadia	Presidency	3,927	5,167,600	New alluvium
North 24 Parganas	Presidency	4,094	10,009,781	Lower delta
South 24 Parganas	Presidency	9,960	8,161,961	Lower delta / Sundarbans
Howrah	Presidency	1,467	4,850,029	Lower delta
Kolkata	Presidency	185	4,496,694	Urban / lower delta
Hooghly	Burdwan	3,149	5,519,145	New alluvium
Purba Bardhaman	Burdwan	5,432	split 2017	Rarh / Damodar
Paschim Bardhaman	Burdwan	1,603	split 2017	Lateritic / industrial
Birbhum	Burdwan	4,545	3,502,404	Rarh
Bankura	Medinipur	6,882	3,596,674	Plateau fringe
Purulia	Medinipur	6,259	2,930,115	Chhotanagpur plateau
Purba Medinipur	Medinipur	4,736	5,095,875	Coastal plain
Paschim Medinipur	Medinipur	6,308	Jhargram split 2017	Plateau fringe
Jhargram	Medinipur	3,037	split 2017	Sal forest / lateritic

Agriculture

The cropping calendar follows three seasons: kharif (June to October), rabi (November to March) and zaid (April to May, often subsumed into the boro rice season). Rice (dhan) is the keystone crop and is grown in three seasonal forms. Aus is the autumn or pre-kharif rice, sown in March and April and harvested between June and August; once a major crop, its area is now substantially reduced. Aman is the winter or kharif rice, sown in June and July and harvested in October and November; this is the principal rice crop. Boro is the summer or rabi rice, sown in January and February and harvested in April and May; it is high-yielding-variety and irrigation-dependent. Total state rice output exceeds 16 million tonnes per annum, of which boro accounts for about 4.7 million tonnes.

West Bengal is the largest producer of jute in India and accounts for about three-quarters of national raw jute output. Production is concentrated in Murshidabad, Nadia, Hooghly, North 24 Parganas, Cooch Behar, Bardhaman and Malda. About sixty of the country's seventy jute mills line the Hooghly. Tea is the principal hill and Dooars crop. Darjeeling tea (sinensis-type, geographical indication) covers about 17,500 ha across some 87 estates. The Terai and the Dooars grow Camellia assamica on about 97,280 ha, processed as CTC. The state supplied 424 million kg of India's 1,390 million kg national output in 2019, or 30.5 per cent of national tea production. Potato is concentrated in Hooghly and the Bardhaman districts. West Bengal is the second-largest producer in India after Uttar Pradesh, contributing about 22.8 per cent of national output. Other significant crops by zone include wheat, oilseeds and pulses (rabi, on the middle Gangetic plain); mango, litchi and mulberry (Malda, Murshidabad and Nadia); pineapple (Siliguri and Jalpaiguri); coconut, betel and brackish-water aquaculture (South 24 Parganas, Purba Medinipur and Howrah); and tasar silk, niger, horse-gram and hardy millets on the lateritic west (Purulia and Bankura).

Demographic and ethnographic geography

At the 2011 Census, West Bengal had a population of 91,276,115 in 88,752 km², a density of 1,028 persons per km² and the second highest among Indian states. The mother-tongue distribution was Bengali 86.22 per cent, Hindi 5.00 per cent, Santali 2.66 per cent, Urdu 1.82 per cent and Nepali 1.26 per cent. Nepali is co-official in the Darjeeling and Kalimpong districts. Hindi, Odia, Punjabi, Santali, Urdu (2012) and Kamtapuri, Kurmali and Rajbanshi (2019) have additional official status in blocks where speakers exceed ten per cent. Telugu was added in 2020.

Scheduled Tribes constituted about 5.8 per cent of the state's population at the 2011 Census. Forty communities are notified. The dominant groups are the Santal (about 52 per cent of the ST population), Oraon (14 per cent), Munda (7.8 per cent), Bhumij (7.6 per cent) and Kora (3.2 per cent). These are concentrated in the southwestern plateau-fringe districts (Purulia, Bankura, Jhargram and Paschim Medinipur) and in the Dooars tea-garden belt (Jalpaiguri and Alipurduar), where many were brought as labour from Chota Nagpur in the late nineteenth century. Other communities include the Lodha and Kheria of Jhargram and Paschim Medinipur (notified PVTG); the Toto of Totopara in Alipurduar (notified PVTG; 1,387 individuals at the 2011 Census, rising to about 1,600 by 2022); the Birhor of Purulia (notified PVTG); the Rabha, Mech and Garo of the Dooars and Terai; the Lepcha, Bhutia, Sherpa, Tamang and Limbu of the Darjeeling and Kalimpong hills; and the Rajbanshi of the North Bengal plains, whose linguistic identity is registered under the Kamtapuri / Rajbanshi heading. The Gorkha (Nepali) community of the Darjeeling and Kalimpong hills is not Scheduled but has shaped the political and administrative history of the hill region through long-standing autonomous-region claims.

The Santal community is the one most extensively recorded in colonial and post-colonial ethnographies of Bengal ganja cultivation, in the historical Ganja Mahal (where Santal women's role in the post-harvest processing is documented by Rahman, Matsushima, Uddin and Sarwar) and across the Indian Rarh.