The Union Stock Yard & Transit Co., or The Yards, was the meatpacking district in Chicago for more than a century, starting in 1865. The district was operated by a group of railroad companies that acquired marshland and turned it into a centralized processing area. By the 1890s, the railroad capital behind the Union Stockyards was Vanderbilt money. The Union Stockyards operated in the New City community area for 106 years, helping Chicago become known as the "hog butcher for the world," the center of the American meatpacking industry for decades. The yards became inspiration for literature and social reform.

The meat-packing industry handles the slaughtering, processing, packaging, and distribution of meat from animals such as cattle, pigs, sheep and other livestock. Poultry is generally not included. This greater part of the entire meat industry is primarily focused on producing meat for human consumption, but it also yields a variety of by-products including hides, dried blood, protein meals such as meat & bone meal, and, through the process of rendering, fats.