The river formed where the White Nile and Blue Nile meet at Khartoum is the Nile.
The White Nile flows northward from the Lake Victoria region through Uganda and South Sudan, while the Blue Nile rises near Lake Tana in Ethiopia. They converge at Khartoum, Sudan’s capital, creating the main stem conventionally called the Nile.
The two tributaries contribute differently. The White Nile is longer and has a steadier flow because lakes and wetlands regulate its water. The Blue Nile, however, supplies more annual water and carries much of the sediment responsible for the Nile’s historic floodplain. Its flow rises sharply during Ethiopia’s summer rainy season.
A common mix-up is treating the White Nile or Blue Nile as the river formed at Khartoum. Both are major tributaries; the name Nile applies downstream of their confluence. The river then continues through Sudan and Egypt before reaching the Mediterranean Sea, where it forms the Nile Delta.