Where does a river end?

Eventually a river meets the sea and the place where it does is called the mouth. The last of the mud is deposited at the river’s mouth. A wide mouth is called an estuary. Some estuaries are enormous – the estuary of the Amazon is 333 kilometres wide!

Sometimes a lowland river winds so much that the looping meanders almost touch. The river may eventually erode away the narrow area of land between two loops so that its course runs straight and a horseshoe-shaped area of water is stranded – an ox-bow lake.