What is the longest river in South America?

The Amazon River is recognized as the longest river in South America, stretching approximately 4,345 miles (7,062 kilometers) from its source in the Andes Mountains to its mouth in the Atlantic Ocean. Its vast river system includes numerous tributaries that contribute to its considerable length, making it not only the longest river in South America but also one of the most significant in terms of biodiversity and ecological importance. The Amazon Rainforest, through which the river flows, is one of the most biodiverse areas on the planet. This river serves as a critical waterway for both the environment and the economic activities of the regions it traverses.

In contrast, while the Nile River is often cited as the longest river in the world, it is located in Africa, and therefore not relevant to the question. The Orinoco River and the Paraná River, while also significant to South America, do not reach the lengths of the Amazon River; the Orinoco is about 1,700 miles long, and the Paraná is approximately 3,000 miles in total length when considering its tributaries. These factors highlight the Amazon's unparalleled status as the longest river in South America.