This distributor of steel products was founded in Chicago in 1890 by A. M. Castle. By the late 1920s, when the company had warehouses around the country, annual revenues were about $7 million. By the beginning of the 1960s, when sales reached about $35 million, Castle was based in suburban Franklin Park, Illinois. At the end of the twentieth century, the company employed about 500 people in the Chicago area and did about $700 million in annual sales.

This entry is part of the Encyclopedia's Dictionary of Leading Chicago Businesses (1820-2000) that was prepared by Mark R. Wilson, with additional contributions from Stephen R. Porter and Janice L. Reiff.