Lake Mead is the largest reservoir in the United States. It is located on the Colorado River about 30 miles (48 km) southeast of Las Vegas, Nevada, in the states of Nevada and Arizona. Formed by water impounded by Hoover Dam, Lake Mead extends 112 miles (180 km) behind the dam, holding approximately 28.5 million acre feet (35 km³) of water, making it one of the largest-capacity reservoirs in the Northern Hemisphere. Lake Mead, with its 550 miles of shoreline, is the focal point of Lake Mead National Recreation Area.