Indiana limestone is a common term for Salem limestone , a geological formation primarily found in southern Indiana. Salem limestone, like all limestone, is a rock primarily formed of calcium carbonate. The limestone was deposited over millions of years as marine fossils decomposed at the bottom of a shallow inland sea which covered most of the present-day Midwestern United States.
The first Indiana limestone quarry was started in 1827, and by 1929 Hoosier quarries yielded 340,000 m³ (12 million cubic feet) of usable stone. Buildings such as the Empire State Building, The Pentagon, and the U.S. Holocaust Museum feature Indiana limestone in their exteriors.
