Lake Mead

Lake Mead is the largest reservoir in the United States by water capacity, formed on the Colorado River by the Hoover Dam and straddling the Nevada-Arizona border about 24 miles east of Las Vegas. It first filled on September 30, 1935, and at maximum capacity holds about 32.2 cubic kilometers of water across a surface area of 247 square miles, reaching a maximum depth of 532 feet. The reservoir supplies water to nearly 20 million people across Arizona, California, Nevada and parts of Mexico as well as extensive agriculture, but it has remained below full capacity since 1983 because of drought and rising demand, reaching a historic low elevation of 1,038.94 feet in August 2026.