Thornton Quarry is one of the largest aggregate quarries in the world, located in Thornton, Illinois just south of Chicago. The quarry is 1.5 miles (2.5 km) long, 0.5 miles (1 km) wide, and 450 feet (137.16 m) deep at its deepest point. Gallagher Asphalt Corporation has been operating on the grounds of the quarry since 1928. A dryland dike carries Interstate 80/Interstate 294/Tri-State Tollway over the quarry.