Chicago's Union Stock Yard was the meatpacking district for Chicago, Illinois. In 1848, small stockyards were scattered throughout the city along various rail lines. Several factors contributed to Chicago's need for a larger, more centralized stockyard: Chicago's evolution into a major railroad hub, the Mississippi River blockade during the Civil War that closed the north-south trade route, and the influx of meatpackers and livestock to Chicago.

In 1864, a consortium of nine railroad companies purchased 320-acres of swamp land in southwest Chicago to build a new more efficient stockyard. The result was that Chicago's Union Stock Yard and Transit Company opened Christmas Day 1865. Livestock was brought to the stockyards by fifteen miles of track that linked to the city's mail railroad lines. By 1900, the stockyard grew to 475 acres, contained fifty miles of road, and had 130 miles of track.

After World War II, new technology led to their obsolescence. The rapid growth of the federal highway system and the development of the refrigerated truck gave packinghouses the freedom to move out of the city they had depended upon for railroad access. Competition led to the building of mechanized meatpacking plants in less expensive rural areas. In addition, meatpackers began doing business with farmers directly, therefore bypassing the need for a stockyard. And increase in land value, property taxes, and anti-pollution laws contributed to the stockyards' decline.

On July 31, 1971, Chicago's Union Stock Yards officially closed. The area has since become an industrial park. Only the giant limestone arch, erected in 1879, that marked the entrance to the stockyards remains.