The Sukla Phanta Wildlife Reserve is a protected area in the Terai of the Far-Western Region, Nepal, covering 305 km2 (118 sq mi) of open grassland, forests, riverbeds and tropical wetlands at an altitude of 174 to 1,386 metres (571 to 4,547 ft). It was gazetted in 1973 as Royal Sukla Phanta Wildlife Reserve. A small part of the reserve extends north of the East-West Highway to create a corridor for seasonal migration of wildlife into the Sivalik Hills. The Syali River forms the eastern boundary southward to the international border with India, which demarcates the reserve’s southern and western boundary.
The Indian Tiger Reserve Kishanpur Wildlife Sanctuary is contiguous in the south; this coherent protected area of 439 km2 (169 sq mi) represents the Tiger Conservation Unit (TCU) Sukla Phanta-Kishanpur, which covers a 1.897 km2 (0.732 sq mi) block of alluvial grasslands and subtropical moist deciduous forests.
The protected area is part of the Terai-Duar savanna and grasslands ecoregion and is one of the best-conserved examples of floodplain grassland.