The Black Hills are in the southwestern part of South Dakota and extend into Wyoming. This range of low mountains covers 6,000 sq. miles (15,500 km2.) with mountains that rise from 2,000 to 4,000 feet (600 to 1,200 m) above their bases. The highest point in South Dakota, Black Elk Peak (formerly named Harney Peak) is 7,242 ft or 2,207 m above sea level and is in the Black Hills. This is the highest point in the United States east of the Rocky Mountains. Other Black Hills mountains that are over 7,000 ft (2,133 m) in elevation include Bear Mountain, Crooks Tower, Terry Peak, and Crows Nest Peak. The Black Hills are rich in minerals such as gold, silver, copper, and lead. The Homestake Mine, the largest and deepest gold mine in North America, was located in the Black Hills and produced over $1 billion in gold since it started operation in 1876. The mine is now a scientific laboratory.