The Koshi Tappu Wildlife Reserve is a protected area in the Terai of eastern Nepal covering 176 km2 (68 sq mi) of wetlands in the Sunsari, Saptari and Udayapur Districts.

It comprises extensive reed beds and freshwater marshes in the floodplain of the Kosi River, and ranges in elevation from 75 to 81 m (246 to 266 ft).

[2] During 1997 to 1998, an interview survey was conducted in the Paschim Kasuha VDC adjacent to the east of the reserve to investigate the extent of park–people conflict.

Local people are responsible for illegal utilization of forest products, poaching and river fishing inside the reserve.

[6] With this upsurge in the population, authorities are planning a possible transfer of some wild water buffaloes to the flood plains of Chitwan National Park where they have been extirpated in the 1950s.

[7] Notable among the 485 bird species are watercock, Indian nightjar, dusky eagleowl, black-headed cuckooshrike, whitetailed stonechat, striated grassbird, large adjutant stork, Pallas’s fish eagle, common golden-eye, and gullbilled tern.