Declared a national park on the 2nd September 1986, having been previously designated a sanctuary in 1966, Somawathiya affords protection to a unique habitat of riverine villus and floodplains, as well as the largest concentration of elephants in the country, along with Flood Plains National Park.
The park is currently not open to the public.
Somawathiya National Park spans the East and North Provinces and has an area of 37,762 hectares. The water filled basins in the central floodplains are characterized by the abundance and predominance of water-tolerant grasses and aquatic plants.
The ecological importance of Somawathiya is due mainly to the abundance of elephants, which is estimated to be around 400 within the park and its immediate environs, and also due to its abundant bird life. Noteworthy mammals include the golden jackal, fishing cat, rusty-spotted cat, leopard, wild boar, Sambar, water buffalo, porcupine and the black-naped hare.
Typically, the marshes of the flood plains have an interesting and abundant avifauna. Around 75 migrant species are known to head here to the marshes in winter, including species such as garganey, marsh sandpiper, pintail snipe and whiskered tern. Resident birds include the painted stork and purple coot among others.