Angammedilla National Park

Lore & Background

Angammedilla National Park lies 225 kilometers from Colombo in Polonnaruwa District. The Amban river, sourced by Sudu Kanda, forms its southern border. A mountain range stretches across the park from Girithale to Minneriya. During drought the park is very dry, while in the rainy season the mountainous area receives more rainfall than the plains. The climate is a mix of wet and dry, resulting in vegetation that blends wet zone and dry zone plants. In ancient times, water was irrigated from the Amban river to Parakrama Samudra via a stone canal, whose rocky wall is called the royal wall by villagers.

Reader's Guide

Angammedilla National Park is significant as a protected area established to safeguard the drainage basins of Parakrama Samudra, Minneriya, and Girithale irrigation tanks, as well as water sources in Sudu Kanda. Its designation in 2006 reflects Sri Lanka's ongoing efforts to conserve critical watersheds and the habitats and wildlife of adjacent forests. The park's vegetation is predominantly dry evergreen forests, with dominant species including Diospyros ebenum, Manilkara hexandra, Cholorocylon swetenia, Vitex pinnata, and Adina cordifolia. Mesua ferrea trees grow in communities. Common fauna include Sri Lankan elephant, sambar deer, Indian muntjac, axis deer, water buffalo, wild boar, and peafowl. Less frequently seen are Sri Lanka leopard, sloth bear, grizzled giant squirrel, and Sri Lanka junglefowl. Primate species present are red slender loris, tufted gray langur, and purple-faced langur. The park's mixed climate and vegetation make it a unique ecological zone.

Did You Know?

• The park is located 225 km from Colombo in Polonnaruwa District.
• The Amban river, sourced by Sudu Kanda, forms the southern border of the park.
• An ancient stone canal irrigated water from the Amban river to Parakrama Samudra, and its rocky wall is called the royal wall by villagers.

Geography & Physical Landscape

Horton Plains sits atop the southern plateau of Sri Lanka's central highlands, where the terrain rises between 1,200 and 2,300 metres above sea level. The park is flanked by two of the island's tallest summits: Kirigalpoththa at 2,389 metres to the west and Thotupola Kanda at 2,357 metres to the north, ranking as the second and third highest peaks in the country. Beneath the surface lie ancient Archean rocks from the Precambrian high series, composed of khondalites, charnockites, and granitic gneisses, while the topsoil belongs to the red-yellow podsolic group, its upper layer blanketed in decomposed organic matter. The climate is cool and wet, with mean annual rainfall exceeding 2,000 millimetres and persistent cloud cover limiting direct sunlight. Temperatures average around 13 °C but swing dramatically between a daytime high of 27 °C and a nighttime low of 5 °C, with ground frost a regular occurrence in February. The park's most dramatic features include World's End, a sheer precipice dropping 870 metres, and Baker's Falls, a 20-metre cascade on the Belihul Oya named for Sir Samuel Baker.

Hydrology & Drainage

Horton Plains is widely regarded as the most critical drainage basin on the island of Sri Lanka. The elevated plateau serves as the headwater source for three of the country's principal rivers—the Mahaweli, the Kelani, and the Walawe—meaning that rainfall collected on these high meadows ultimately feeds vast downstream populations and ecosystems. Beyond these three major waterways, the plains also give rise to several smaller tributaries, including the Belihul Oya, Agra Oya, Kiriketi Oya, Uma Oya, and Bogawantalawa Oya. The landscape is dotted with natural pools, slow-moving streams, and waterlogged swamps in its low-lying areas. Baker's Falls, a 20-metre drop on the Belihul Oya (itself a tributary of the Walawe), is one of the park's most recognisable water features, while Slab Rock Falls offers another notable cascade. In the wetter, marshier zones, macrophytic plants such as Aponogeton jacobsenii, the floating sedge Isolopis fluitans, and bladderwort species of Utricularia thrive along the sluggish watercourses, while the bamboo Chimonobambusa densifolia lines the stream banks. The sheer volume of water generated here underscores why protecting this plateau is essential for the hydrological health of the entire island.

Flora & Ecosystem

The park's vegetation falls into two broad categories: approximately 2,000 hectares of wet patana, the Sinhalese term for montane grasslands and shrublands, and roughly 1,160 hectares of subtropical montane evergreen forest. Together they support close to 750 recorded plant species across 20 families. The forest canopy can reach 20 metres and is dominated by Calophyllum walkeri, which forms mixed communities with Myrtaceae members like Syzygium rotundifolium and S. sclerophyllum, as well as Lauraceae species including Litsea, Cinnamomum, and Actinodaphne speciosa. Beneath the canopy, dense thickets of Strobilanthes suppress the development of a true herb layer, while dwarf bamboos of the genera Indocalamus and Ochlandra fill the undergrowth. Of the 54 woody plant species documented, a remarkable 27—half the total—are endemic to Sri Lanka. The grasslands, shaped by recurring fire and grazing, are dominated by Arundinella villosa and Chrysopogon zeylanicus. Horton Plains also holds the distinction of containing the most extensive surviving cloud forest on the island, a habitat that shelters numerous species found nowhere else.

History & Conservation

The plateau was long known to local inhabitants as Maha Eliya Thenna, meaning 'great open plain.' During the British colonial era, the area was renamed in honour of Sir Robert Wilmot-Horton, governor of Ceylon from 1831 to 1837, who visited the region in 1836 to meet the Ratemahatmaya of Sabaragamuwa. The plateau had been formally 'discovered' by the British in 1834 by Lieutenant William Fisher of the 78th Regiment and Lieutenant Albert Watson of the 58th Regiment. Archaeological evidence, including stone tools linked to the Balangoda culture, points to far earlier human presence. Conservation efforts began in earnest when botanist Sir Joseph Dalton Hooker urged the colonial government to leave montane forests above 5,000 feet untouched, leading to a protective administrative order in 1873. The area was first gazetted as a wildlife sanctuary on 5 December 1969, then elevated to full national park status on 18 March 1988. In July 2010, the broader Central Highlands region—encompassing Horton Plains, the Peak Wilderness Sanctuary, and the Knuckles Mountain Range—was inscribed on the UNESCO World Heritage List, recognising its outstanding universal value.