Udzungwa National Park is unlike most of Tanzania's other national parks: no jeep safaris, no game drives. This is a walking park, deep in dense highland forest, and its rewards are quiet and particular. It sits along the major fault line that delimits the eastern side of the Southern Highlands, where prevailing westerly winds rise, cool, and drop rain almost constantly. The result is continuous forest running from around 200 m altitude up past 2,000 m — an almost unbroken green column rare anywhere in Africa.
The park lies within the Eastern Arc, a chain of ancient forest mountains running from the Southern Highlands through the Uluguru and Usambara ranges northwards to Pare. These forests are world-famous for biodiversity. Three primates found nowhere else on earth live here: the Sanje crested mangabey, the Matundu galago, and the Iringa red colobus. Visitors regularly spot the red colobus; the Usambara violet (Saintpaulia) also has one of its southwesternmost outposts in these forests.
Walking is permitted along marked trails, and a guide is compulsory — you hire one at the park gate near Mang'ula, where fees are also paid. The shortest option is the Prince Bernhard Trail, a gentle 1 km walk to a waterfall. The more rewarding route climbs to Sanje Falls, a series of three consecutive waterfalls; below the upper two, swimming in the stream is excellent (avoid it after heavy rain when the water runs high). Longer trails with camping are available for those who want to go deeper into the forest. The slopes are steep and trails can be slippery — come prepared.