The Shuklaphanta National Park 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 m (571 to 4,547 ft). It was gazetted in 1976 as Royal Shuklaphanta 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 area was a favorite hunting ground for Nepal’s ruling class and was declared a Royal Hunting Reserve in 1969. In 1973, the area was gazetted as Royal Sukla Phanta Wildlife Reserve, initially comprising 155 km² (60 sq mi), and extended to its present size in the late 1980s. A buffer zone of 243.5 km² (94.0 sq mi) was added in May 2004.  In 2017, the status of the protected area was changed to a national park.

The name Suklaphanta was derived from one of the grasslands found inside the protected area. The main grassland called Sukla Phanta is the largest patch of continuous grassland in Nepal covering an area of about 16 km² (6.2 sq mi).

The jungles of the Shuklaphanta National Park were once the site of an ancient kingdom. To this day, the ruins of that kingdom can be seen in some places. Near Rani Tal, a lake in the reserve, there still remains a brick girdle, measuring 1,500 m (59,000 in) in circumference. It is considered by locals to be a remnant of the fort of Tharu king Singhal.

The climate of the region is subtropical monsoonal with a mean annual rainfall of 1,579 mm (62.2 in) that occurs from June to September and is highest in August. The winter months of December and January are fairly cold with daytime temperatures of 7–12 °C (45–54 °F) and occasional frost. From February onwards temperatures rise up to 25 °C (77 °F) in March and reach 42 °C (108 °F) by end of April. When the first pre-monsoon rains reach the area in May, humidity increases.

Some 700 species of flora are estimated in the park including 553 vascular plants, 18 pteridophytes, 410 dicots, and 125 monocots. Grassland constitutes almost half the reserve’s vegetation. The main grass species are Imperata cylindrica and Heteropogon contortus. khagra reed (Phragmites karka) and Saccharum spontaneum grow in the marshes surrounding the seven small lakes. The dominant forest type is sal. Khair and sissoo grow alongside rivers. Grassland encroachment by tree and shrub saplings are major threats to the long-term existence of the main phantas.

The extensive open grasslands and wetlands around the lakes of the park are habitat for a wide range of fauna. In the rivers, lakes, and ponds 28 fish species and 12 reptile and amphibian species were recorded. These include mahseer and rohu, mugger crocodile, Indian rock python, monitor lizard, Indian cobra, common krait and Oriental rat snake.