What Are the Parts of a River?

A river is a natural watercourse flowing from higher elevation to a lower one, eventually emptying into an ocean, lake, or another river. Its main parts include:

• Source: The starting point—a spring, melting glacier, or confluence of streams.
• Upper Course: Near the source; steep gradients, fast-flowing water.
• Middle Course: Between upper and lower; moderate gradients, meandering channels.
• Lower Course: Near the mouth; low gradients, slow-moving water.
• Mouth: Where the river empties into another body of water.

Additional features:

• Tributaries: Smaller streams feeding the main river.
• Floodplains: Low-lying land adjacent to the river prone to flooding.
• Deltas: Fan-shaped sediment deposits at the river mouth.