Royal Chitwan National Park was established in 1973. It occupies an area of 932 sq. kms. It is the oldest National park in Nepal . It is situated in the sub-tropical inner Terai lowlands of South-Central Nepal . The Park was designated as a World Heritage Site in 1984.
Within the park lie the Churia hills, ox-bow lakes, and the flood plains of Rapti, Reu and Narayani Rivers . The Churia hills rise gradually towards the east from 150m. to over 800m. elevation. The lower but more rugged Someshwor hills occupy most of the western portion of the park. The flood plains of Chitwan contain rich alluvial soils. The Narayani and Rapti Rivers have delineated the park boundaries in the north and west, and the Reu river and Someshwor hills in the south and south-west. It shares its eastern border with the Parsa Wildlife Reserve.
There are over 450 species of birds in the Park. Among the endangered birds are the Bengal jolrican, giant hornbill, lesser florican, black stork and white stork. Common birds seen in the Park inclde the peafowl, red jungle fowl, and different species of egrets, herons, kingfishers, flycatchers and woodpeckers. The best time for bird watching is March and December. More than 45 species of amphibians and reptiles occur in the Park, some of which are the marsh corcodile, cobra, green pit viper and various species of frogs and tortoises. The Park is actively engaged in the scientific studies of several species of wild fauna and flora. There are more than 43 species of mammals in the Park. The Park is especially renowned for the endangered one-horned rhinoceros, the tiger and the gharial crocodile. It also harbors endangered species such as gaur, wild elephant, four-horned antelope, striped hyena, pangolin, Gangetic dolphin, monitor lizard and python. Other animals found in the Park include the sambar, chital, hog deer, barking deer, sloth bear, palm civet, langur and rhesus monkey.
The park is influenced by a tropical monsoon climate with relatively high humidity. Winter, spring and monsoon are the three main seasons. The cool winter season occurs from October to February. Spring begins in March and is soon followed summer that ends in early June. Summer days are typically hot with up to an average 30C daytime temperature. The monsoon usually begins at the end of June and continues until September. The mean annual rainfall is about 21-50 mm. and during this time of the year rivers are flooded and most of the roads are virtually impassable.