The Nile River, Africa (running through 10 countries) 6,650 km (4,132 miles)
The Amazon River, South America (running through 6 countries) 6,400 km (3,976 miles) – Read more about How to plan a trip to Amazon river using online trip planner?
The Yangtze River, Asia (China) 6,300 km (3,915 miles)
The Mississippi/Missouri River, North America (The United States) 6,275 km (3,899 miles)
The Yenisei/Angara/Selenga River, Europe/Asia (Russia/Mongolia) 5,539 km (3,441 miles)