Koshi Tappu Wildlife Reserve was established in 1976 with primary objective to protect the rare wild water buffaloes in this region. The area of this reserve extends 175 sq. km area with wet and grassland habitat in the Terai of eastern Nepal. It covers the vast expanse of region created by the Koshi barrage, marshes, lagoons and arable land with blue water of Koshi River and jungle area. It is one of the best and finest bird watching sanctuaries in Asia. It offers ample scope for nature walks on foot to explore fabulous grassland, river lagoons and woodlands.
From October to March, much of migratory and local birds can be sighted by the barrage and many of the river channels. Himalayan peaks including the Makalu (8463m) can be seen clearly during these months from this amazing wildlife reserve. This reserve is accessible by air, land and river. There is a regular flight of just 45 minutes to Biratnagar from Kathmandu. An exciting 8-10 days raft trip on Sun Koshi River reaches directly at this wildlife Reserve.