- Green River - The Green River is the largest tributary of the Colorado River, joining it in Canyonlands National Park in Utah. It is 730 miles (1,175 km) long and drains an area of 40,000 square miles (104,000 km2) in Wyoming, Colorado, and Utah.
- San Juan River - The San Juan River is the second largest tributary of the Colorado River, joining it near the town of Bluff, Utah. It is 383 miles (616 km) long and drains an area of 24,000 square miles (62,000 km2) in Colorado, New Mexico, Arizona, and Utah.
- Little Colorado River - The Little Colorado River is a major tributary of the Colorado River, joining it near the town of Lees Ferry, Arizona. It is 320 miles (515 km) long and drains an area of 27,000 square miles (70,000 km2) in Arizona and New Mexico.
- Gila River - The Gila River is a major tributary of the Colorado River, joining it near the city of Yuma, Arizona. It is 649 miles (1,045 km) long and drains an area of 58,000 square miles (150,000 km2) in Arizona and New Mexico.
- Virgin River - The Virgin River is a major tributary of the Colorado River, joining it near the town of Mesquite, Nevada. It is 264 miles (425 km) long and drains an area of 12,000 square miles (31,000 km2) in Utah, Nevada, and Arizona.
