One of the largest and oldest calderas (an extinct and collapsed volcano) in the world, Mount Elgon is 80 km in diameter and, in remote times, was higher than Kilimanjaro. It marks Uganda's border with Kenya and has five scalable peaks between the two countries: Koitobos (4,187 meters) is the second highest point in Kenya, and Wagagai the highest peak in Elgon and the seventh in Uganda (4,321 meters). The rainforest at the base turns into a bamboo jungle, heath zone and closer to the top, moorland zone.

Endemic animals of the region include elephants, buffalo, bushbucks, baboons, wild boars and duikers. The lower forests are the habitat of black and white colobus and blue and Brazza's monkeys. There are more than 240 species of birds, including red-fronted parrots, Ross's turtles and bush hornets. Many can be seen during the climb, possible either on Ugandan or Kenyan sides: both are protected by independent national parks.