The Colorado River is one of the principal rivers of the Southwestern United States and northern Mexico. Rising in the central Rocky Mountains, it flows 2,330 kilometers into the Gulf of California. The river is most famous for its role in carving the Grand Canyon over millions of years, exposing nearly two billion years of Earth's geological history. Today, the Colorado is a vital resource for the arid West, providing water for over 40 million people and irrigating nearly 5.5 million acres of farmland. However, it is also one of the most heavily dammed and diverted rivers in the world. Major dams like the Hoover and Glen Canyon dams control its flow for electricity and water storage. Because of these diversions, the river rarely reaches the sea, resulting in the collapse of the Colorado River Delta's ecosystem in Mexico.