Mount Elgon, on the Uganda–Kenya border, contains one of the world’s largest intact volcanic calderas.
The mountain is an ancient, extinct shield volcano whose summit area was eroded and reshaped over time. Its broad caldera measures roughly 8 kilometres across, making it a major geological feature rather than a sharp volcanic cone.
Mount Elgon’s highest point is Wagagai, at 4,321 metres, on the Ugandan side of the border. The mountain supports varied habitats, including montane forest, bamboo zones, moorland, and distinctive giant groundsels. Mount Elgon National Park protects parts of the mountain in both countries.
It is sometimes confused with Mount Kenya or Kilimanjaro because all three are major East African mountains. Mount Kenya and Kilimanjaro are higher, but Elgon is especially notable for its immense ancient caldera and cross-border volcanic landscape.