Nepal's first and most famous national park is situated in the Inner Terai lowlands of Chitwan. Covering an area of 932 sq. kilometers the park includes hilly areas of the Shivalik Range covered by deciduous trees. Parts of the park are floodplains of rivers Narayani, Rapti, and the Reu, covered by dense tall elephant grass, forests of silk cotton, acacia and Sisam trees. Royal Chitwan National Park was officially established in 1973 and included as World Heritage Site in 1984.

The park in Chitwan is shelter to the last endangered Asian species like the one-horned rhinoceros and the Royal Bengal tiger. Other animals found here are the leopard, sloth bear, wild boar, rhesus monkey, grey langur monkey, wild dog, small wild cats, bison, the four species of deer and other small animals. Marsh crocodiles inhabit the swampy areas. The Gangetic crocodile that only feed on fish, are found in a stretch of the River Narayani. Also found here is one of the four species of fresh-water dolphins.

Chitwan park is also home to 450 species of bird and hence is ideal for bird watching. Some of the resident specialties are woodpeckers, hornbills, Bengal florican, red-headed trogons, waterfowl, Brahminy duck, pintails and bareheaded geese. In summer the forest is alive with nesting migrants such as the fabulous paradise flycatcher, the Indian pitta and parakeets.