List of river systems by length

Other factors that can change the length of a river include cycles of erosion and flooding, dams, levees, and channelization.

In addition, the length of meanders can change significantly over time due to natural or artificial cutoffs, when a new channel cuts across a narrow strip of land, bypassing a large river bend.

For example, due to 18 cutoffs created between 1766 and 1885, the length of the Mississippi River from Cairo, Illinois, to New Orleans, Louisiana, was reduced by 351 kilometres (218 miles).

(Heilong Jiang) Missouri The Amazon basin formerly drained westwards into the Pacific Ocean, until the Andes rose and reversed the drainage.

[79] The Congo basin is completely surrounded by high land, except for its long narrow exit valley past Kinshasa, including waterfalls around Manyanga.

Current scientific research favours the former opinion, with the Thames and Rhine meeting in a large lake, the outflow of which was close to the present-day Straits of Dover.

The Nile as seen from a cruise boat between Luxor and Aswan in Egypt
The Mississippi River just north of St. Louis
Saint Lawrence River along the New York-Quebec border