The Hummelstown Brownstone Quarry was founded around 1863 by Allen Walton and at its height employed 500 men. Many of the skilled workers employed at the quarry were Scotch-Irish, German, and Italian immigrants that brought with them extensive stone working experience. Because of its durability and capacity to be worked from all angles, brownstone was an extremely popular building material throughout the 19th century. It was often used to face entire buildings or as ornate ornamentation and decorative sculpture. Many buildings throughout the Middletown and Hummelstown area are built of or stand on foundations of stone from the Hummelstown quarries.