Parsa Wildlife Reserve is a protected area in the Inner Terai lowlands of south-central Nepal. Established in 1984, it covers an area of 499 km2 (193 sq mi) in the Parsa, Makwanpur and Bara districts and is the largest wildlife reserve in the country. In altitude it ranges from 435 metres (1,427 ft) to 950 metres (3,120 ft) in the Siwalik Hills.
In the north of the protected area the Rapti River and Siwalik Hills form a natural boundary to human settlements. In the east it extends up to the Hetauda - Birgunj highway.
In the south, a forest roads demarcates the boundary. Adjacent to the west is Chitwan National Park. Together with the Indian Tiger Reserve Valmiki National Park, the coherent protected area of 2,075 km2 (801 sq mi) represents the Tiger Conservation Unit (TCU) Chitwan-Parsa-Valmiki, which covers a 3,549 km2 (1,370 sq mi) block of alluvial grasslands and subtropical moist deciduous forests.