Nepal holds a total of ten national parks and three wildlife reserves, but the ones you are most likely to want to visit are both in the south of country, near the Indian border in the so-called Terai region.
Famed above all for its population of one-horned rhinos, Chitwan is the most popular and commercialized, and the closest to Kathmandu. Bardia, in the southwest, requires more effort to reach, and offers a narrower choice of accommodation, but tends to be much quieter and encompasses a broader range of habitats. It’s also a fantastic place for bird watching.
One of the great attractions of both of these parks is that you can explore their swampy grasslands and sub-tropical forests on elephant back, which allows you to get much closer to the rhinos than you can in a Jeep, and also increases your chances of a tiger sighting.
Winter, from October to early April, is the best time to visit. In summer, the monsoon rains make any kind of safari challenging, and transport connections are frequently disrupted by flooding.