Africa's longest river is the Nile, which is 4 letters long. The Nile is a major north-flowing river in northeastern Africa, and is commonly regarded as the longest river in the world, measuring over 4, 000 miles in length. It is also an important source of water for Egypt and Sudan, and is the primary water source for the countries that it flows through. The Nile has been an important part of African culture and history for centuries, and continues to be an important part of life in many parts of the continent today.