Worth visiting important natural sites in Ancient Kapilavastu include Jagadispur Reservoir (enlisted as a RAMSAR site), Bhagirathi River, Agigara Lake (20km south of Taulihawa), Shankarpur Tal, Bajaha Tal, Tilaurakot Sajhedari Forest, Churia Forest etc.
Jagadishpur Reservoir is the largest man-made reservoir in Nepal and enlisted as one of the Wetlands of International Importance, known as RAMSAR site in 2003. It spreads in an area over 225 hectares with 157 hectares covered by water surface. Maximum depth of the lake is 5 meters in south-west with an average depth of 3 meters. It has a capacity to hold 47,500,000 cubic liters of water and a home to at least 61 species of birds, 11 of these are rare. Apart from being a natural habitat to the indigenous ones, the lake lies on the flight path of migratory birds from Siberia, Russia, China, Mongolia, Central Asia, Turkmenistan and Kirgizstan. It is also a home to 9 species of turtles, 25 species of snakes, 23 species of mammals, 39 to 47 species of fish and 14 species of lizards. The lake irrigates 6350 hectares of surrounding agricultural field benefitting more than 6700 households.