Historian Elaine Lewinnek in The Working Man’s Reward summarizes where Chicago’s Black residents lived in the late 1800s:

By 1870 Chicago’s five thousand black residents lived in every ward of the city as well as numerous suburbs. Chicago had instituted some progressive policies during Reconstruction, including a civil rights law and, in 1874, an officially desegregated school system. After the collapse of Reconstruction, many blacks who had held political office in southern states relocated to Chicago in what observers called “the Migration of the Talented Tenth.” By 1893 Chicago’s black population was fifteen thousand, still just a small fraction of the more than million Chicagoans. Some blacks settled north of Chicago, near domestic service jobs in the suburb of Evanston, as well as on the near West Side. Many gathered in the neighborhood around Clark and Harrison Streets, on the south fringe of Chicago’s business district, an area that escaped the Great Fire of 1871 but was completely burned in 1874.
During the 1880s and 1890s, pushed by racism and pulled by their own preferences for living near black-led institutions, new black migrants were increasingly limited to Chicago’s Black Belt on the South Side. Extending just two blocks west and east of State Street, stretching south to Thirty-fifth Street and eventually Fifty-fifth, this narrow strip contained 56 percent of Chicago’s blacks in 1900, 78 percent, and 90 percent by 1930. (152-153)
This mirrors national trends. W. E. B. Du Bois discusses this in The Souls of Black Folk where he looks at what was possible during Reconstruction and then quickly disappears once that period ends. James Loewen argues in Sundown Towns that after the movement of Black residents all over the United States after the Civil War, many communities in the United States by the late 1800s restricted Black people and other people of color from staying or living in their towns.
And Chicago is a particularly noteworthy example of this because of how strong these geographic lines become. By the early 1900s, violence, formal and informal policies, and social interactions reinforce these boundaries in such a way that Chicago is one of the most racially segregated cities in the United States by the end of the century.
But these boundaries were not always there. They do not have to be there in the future. Lewinnek argues they were the result of particular actions and conditions, including the efforts of working-class homeowners.








