The river that is a significant waterway in the Amazon rainforest is the Amazon River. It is the second-longest river in the world, flowing over 4,000 miles and discharging more water than any other river. The Amazon River has immense ecological significance, supporting one of the most diverse ecosystems on the planet. Its basin plays a vital role in the global climate, influencing weather patterns, and is an essential resource for local indigenous communities as well as countless species of plants and wildlife.