Since the opening of the Union Stock Yard in 1865, the livestock market and packinghouses attracted a diverse population of workers and others to the neighborhoods surrounding Packingtown. Wave after wave of European immigrants joined native-born Americans, both Black and White, in the neighborhoods of Bridgeport, Canaryville, Back of the Yards, McKinley Park, Bronzeville, and other South Side areas.

In the early years of the stockyards, U.S.-born Whites settled in the area. Large numbers of Irish, German, Austrian, and Czech immigrants soon joined them and found employment in the meat industry. These groups quickly dominated the workforce. During the late 1880s, Polish immigrants arrived in large numbers in Back of the Yards and Bridgeport. By World War One, they came to dominate the immigrant population of Back of the Yards while Lithuanians, Slovaks, Carpatho-Rusyns, Russians, Ukrainians, East European Jews, French Canadians, and others settled in the neighborhood. African Americans entered the packinghouse workforce in the early 1900s. During World War One, their numbers increased and continued to grow until 1960, and they largely settled in the Bronzeville neighborhood. In the 1920s, Mexican immigrants and Mexican Americans joined the ethnic mix of the neighborhood. The Mexican immigrant population faced forced repatriation during the Great Depression and began to grow again during WWII. By the late 1950s, more than eighty percent of packinghouse workers were people of color, primarily Mexicans and African Americans. Today, Back of the Yards continues to thrive as a Mexican/Latino community while having remnants of its Slavic roots. The African American community continues to grow, particularly at the neighborhood’s south edge.