Mt. Elgon is an extinct volcano that first erupted more than 24 million years ago. With the largest surface area of any extinct volcano in the world (50 km by 80 km ), Mt. Elgon is the fourth highest mountain in Eastern Africa, with the second-highest peak in Uganda (Wagagi Peak – 4321 metres ). Mt. Elgon contains crater covering over 40 kms at the top of the mountain, surrounded by a series of rugged peaks.