The Koshi Tappu Wildlife Reserve is located in eastern Nepal on the Sapta-Koshi flood plain, one of the three major tributaries of the Ganges. It extends to the Indian border south of the Sapta Koshi. Most of it is tall grassland with a few patches of khair-sissoo scrub forest and deciduous mixed riverine forest. The Eastern Himalaya, which includes Makalu (8475 m), the fifth-highest mountain in the world, lies in the background. With a kilometer-long barrier that spans the Koshi River, the reserve's territory stretches 175 square kilometers to the north.

One of the best and finest bird watching sanctuaries in Asia is found in this wide expanse of water, which is made possible by the barrage, marshes, lagoons, mudflats, and arable land that surround it. Koshi Tappu Wildlife Park's abundance of opportunities for nature hikes is one of its most gratifying and valuable features. Walking is the most fruitful approach to explore the grassland, river lagoons, and woodlands for individuals who have a keen sense of adventure and persistence. The greatest time to visit this wonderful wildlife reserve is from October to March, when many of the local and migratory species may be seen by the barrage and several river channels.