Horton Plains (Maha Eliya) National Park is the national park which located in the highest altitude in Sri Lanka covered by montane grassland and cloud forest. Situated from 32 km from the Central Highlands, Nuwara Eliya, the Horton Plains National Park lies at an altitude of 2,100–2,300 metres.

The vegetation of the park is classified into two distinctive groups, wet patana ("montane grasslands") and subtropical montane evergreen forests. Nearly 750 species of plants belonging to 20 families have been recorded from the park and nearly 54 woody plant species, of which 27 (50%) are endemic to Sri Lanka. Hanging lichens such as Usnea barbata are also common in Horton Plains National Park. A number of ferns and orchids can be seen and 16 of the orchid species being endemic to Sri Lanka.

The vertebrate fauna of the region includes 24 species of mammals, 87 species of birds, 9 species of reptiles and 8 species of amphibians. A large herd of Sri Lankan Sambar Deer roam the park and other mammal species found in the park include Kelaart's Long-clawed Shrews, Toque Macaques, Purple-faced Langurs, Rusty-spotted Cat, Sri Lankan Leopards, Wild boars, Stripe-necked Mongooses, Sri Lankan Spotted Chevrotains, Indian Muntjacs, and Grizzled Giant Squirrels. Fishing Cats and European Otters visit the wetlands of the park to prey on aquatic animals. A subspecies of Red Slender Loris, the Horton Plains Slender Loris (Loris tardigradus nycticeboides formerly sometimes considered as Loris lydekkerianus nycticeboides) is found only in highlands of Sri Lanka and is considered one of the World's most endangered primates.

Along with Ohiya, Pattipola and Ambewela, Horton Plains forms one of the Important Bird Areas (IBAs) in Sri Lanka. Together with the adjacent Peak Wilderness Sanctuary, Horton Plains contains 21 bird species which occur only on Sri Lanka. Four, Sri Lanka Blue Magpie, Dull-blue Flycatcher, Sri Lanka White-eye, and Sri Lanka Wood-pigeon, occur only in Horton plains, while other endemic species include Sri Lanka Spurfowl, Sri Lanka Junglefowl, Yellow-fronted Barbet, Orange-billed Babbler, Sri Lanka Bush-warbler, and Sri Lanka Whistling-thrush. All six highland endemic birds are found here, including Dull-blue Flycatcher, Sri Lanka White-eye, Sri Lanka Wood-pigeon, and Sri Lanka Bush-warbler. Yellow-eared Bulbul and Black-throated Munia are widespread throughout the highlands.

This is the only National Park in Sri Lanka in which visitors are allowed to walk. The most attractive tourist destination in the Horton Plains is the 'Worlds End’ where the 2000 meters plateau comes to an abrupt end, plunging 700-1000 meters to the valley floor. The 'Little Worlds End' is another popular location, falling a mere 300 meters, along with Baker's fall.