The Aberdares is the established name of a mountain range which thrusts directly north from Nairobi for more than 160 kms. The range was named after then President of the Royal Geographical Society by the intrepid Scot, Joseph Thomson, who explored the region in 1883. The Kikuyu name Nyandarua is slowly gaining prominence.

The Aberdare National Park encompasses all land over 3200m together with a projection due east, known as the Salient, which reaches down to 2130m near Nyeri town. The park is a fairyland, awesome in its majesty and beauty. But crossing these mountains is an unpredictable event since rain is both frequent and heavy. The highest point of the range is Ol Doinyo Satima (the mountain of the young bull in Maa language of the Masai), which reaches 3998m. At an elevation of about 3350m along the Naivasha to Nyeri road, strange six meter tall mutants of alpine plants - groundsel, erica, hypericum, lobelia and sennecio - grow in profusion. Icy rivers plunge in glorious cascades and spectacular waterfalls.

The salient which thrusts a dense forest through rich farmland is where both Tree Tops and the Ark are situated. The salient's origin lies in an elephant migration route between the two mountains, now sadly no longer. But the forest is rich in wildlife; elephant and rhino, warthog, bush pig and giant forest hog, waterbuck, duiker, suni, dikdik, bongo and reebuck are all to be seen. In the canopy the black and white colobus monkey performs its aerial acrobatics and Sykes' monkey and black faced vervet can also be found.

The carnivores are represented by lion, usually more hairy and spotted than on the plains, leopard and serval, the latter often seen on the moorlands and sometimes in its melanistic state.

Birds are not only plentiful, but dazzling. The crowned eagle (which eats monkeys) is everywhere and the forest echoes to the shrill cries of the silvery-cheeked hornbill. The resplendent sunbirds are well represented, among them the brilliant metallic violet Tacazze, the emerald green Malachite Sunbird and on the moorlands the Scarlet tufted Malachite Sunbird, with its very long slender tail.

The number of visitors to Aberdare National Park is high, mainly due to the popularity of Tree Tops and The Ark. The park itself is still very much under-visited despite its grandeur and its powerful vistas.

Fauna & Flora:
Rich alpine and sub-alpine flora giving way at lower altitudes to bamboo forests and montane forests. Mammals of the forest zone include blue monkey, colobus, leopard, elephant, warthog black rhino, giant forest hog, bushbuck, buffalo, red duiker, and suni. The open moorlands have eland, several species of duiker, and the rare bongo. More than 200 bird species have been recorded.