The Berkeley Pit was opened in 1955 and became the largest truck-operated open pit copper mine in the United States. The pit enabled
Butte to claim the title "Richest Hill on Earth."
Before the mine was shut down in 1982, more than one and a half billion tons of copper ore were removed. The total depth of the pit from the bottom to the highest rim is 1,780 feet. The viewing stand is open from March until November and no admission is charged.