The Hull–Rust–Mahoning Open Pit Iron Mine in Hibbing, Minnesota, United States, is the largest operating open-pit iron mine in Minnesota. The pit stretches more than three miles (5 km) long, two miles (3 km) wide, and 535 feet (163 m) deep.^[2] It was established in 1895 and was one of the world's first mechanized open-pit mines.^[3]

The mine, located in the Mesabi Range, supplied as much as one-fourth of all the iron ore mined in the United States during its peak production from World War I through World War II. This prodigious output made Minnesota the nation's largest iron ore producer and the U.S. the world's largest steel manufacturer.^[3]

The Hull–Rust–Mahoning Mine was named a National Historic Landmark in 1966.^[1] The city of Hibbing has long maintained a public overlook and visitor center on the rim of the mine, attracting tens of thousands of tourists each year. In 2019, the overlook was to be moved as mining operations expand.^[4]