What is the main religion in East Africa?

Islam is predominant in the coastal areas of Tanzania and Kenya, however as one moves further inland remnants of the colonial period have made their mark and an equal proportion of different Christianity groups are very widespread.

East Africa has a fairly high percentage (approx 15%) of practicing traditional religions, and main groups include the Maasai and Haya.

It is also worth noting that definitions for East Africa are extremely varied. These can include the geographical East Africa (so everything from Egypt south to Mozambique), or definition by language amongst others.

My definition is the common placed definition, which includes Kenya, Uganda, Tanzania, Burundi and Rwanda.

I have not included the Horn of Africa (Eritrea, Dijouti, Ethiopia, Sudan, Somalia).