Gal Oya National Park in Sri Lanka was established in 1954 and serves as the main catchment area for Senanayake Samudraya, the largest reservoir in Sri Lanka. Senanayake Samudraya was built under the Gal Oya development project by damming the Gal Oya at Inginiyagala in 1950. An important feature of the Gal Oya National Park is its elephant herd that can be seen throughout the year. Three important herbs of the Ayurveda medicine, Triphala: Terminalia chebula, Terminalia bellirica, and Emblica officinalis, are amongst the notable flora of the forest. From 1954 to 1965, the park was administered by the Gal Oya Development Board until the Department of Wildlife Conservation took over administration. The National Park is situated 314 km from Colombo.

Thousands of pilgrims visit Dighavapi stupa annually, which is also situated in the area. The stupa was built in the 2nd century BC on the site where Buddha is supposed to have meditated on his third visit to Sri Lanka. Danigala has historical importance as it was the home to the Henebadde Veddas. A rock near the Henebedde cave contains Brahmi inscriptions.

The vegetation of the forest is of three types: forest, shrub, and grassland. The national park contains a substantial area of Savanna grasslands known as Thalawa in Sinhalese and mountainous grasslands known as Pathana.

32 terrestrial mammals have been recorded in the park. The Sri Lankan Elephant, Sri Lankan Axis Deer, Muntjac, Water Buffalo, Sri Lankan Sambar Deer, Sri Lanka Leopard, Toque Monkey, and Wild Boar are among them. Included amongst the reptile species of the park are the Mugger Crocodile and Star Tortoise. More than 150 species of birds have been recorded in Gal Oya. Gal Oya National Park’s butterfly species include the endemic Lesser Albatross.