Bengal tigers live in the Indian subcontinent, in India, Bangladesh, Nepal, Bhutan, and southwestern China. Within that range they use a wide variety of habitats: tropical moist evergreen forests, tropical dry forests, tropical and subtropical moist deciduous forests, mangrove swamps, subtropical and temperate upland forests, and tall alluvial grasslands.
The grassland and riverine forest habitat that once stretched across the Ganges and Brahmaputra plains has largely been converted to farmland, so its best remaining examples are protected areas at the foot of the Himalayas, such as the Corbett, Chitwan, Bardia, and Dudhwa landscapes. The tidal mangrove forests of the Sundarbans on the India and Bangladesh border are another well-known stronghold. The species historically ranged west into the Indus valley of Pakistan, but it disappeared there in the early 1900s, and habitat loss and fragmentation remain major threats today.
Source: Wikipedia: Bengal tiger
Image: Bengal tiger in Sanjay Dubri Tiger Reserve, by Tisha Mukherjee, CC BY-SA 4.0, via Wikimedia Commons.