Lake Mead is a reservoir formed by the Hoover Dam on the Colorado River in the Southwestern United States. It is located in the states of Nevada and Arizona, east from Las Vegas Strip. It is the largest reservoir in the United States in terms of water capacity. Formed by the Hoover Dam on September 30, 1935, the reservoir serves water to the states of Arizona, California, and Nevada, as well as some of Mexico, providing sustenance to nearly 20 million people and large areas of farmland.