Racial segregation existed throughout the United States, North, and South. As one historian of segregation has written, "no reflective historian any longer believes" that Northern states were innocent of the historical crimes of slavery and later segregation. By the twentieth century, Jim Crow laws were not generally on the books of Northern states and cities (though they had been in the nineteenth century.) Nor were racial attitudes as hardened in Northern states as in the Jim Crow South. But segregation, and the racist assumptions that undergirded it, existed north of the Mason-Dixon line too. The difference between segregation in the two regions is usually summarized as "de facto" versus "de jure." Southern racial hierarchies were in fact rigidly enforced by laws that established inflexible boundaries, intended not just to segregate but to establish and maintain white supremacy. In Northern cities in particular, though, segregation was enforced by other means. Neighborhoods, particularly the suburbs that boomed after World War II, established "restrictive covenants" that forbade property owners from selling to African American families. The famous Levittown developments, for example, remained accessible to whites only well into the 1960s due to such agreements. The federal government "redlined" minority neighborhoods, denying government-insured loans to individuals who lived in these areas irrespective of their credit-worthiness. School district lines were drawn in order to establish "neighborhood" schools that were very often highly segregated, and as the infamous riots that gripped Boston in response to busing measures in 1974 demonstrated, ordinary Northerners responded with violence to attempts to integrate neighborhoods and schools. Of course, racial segregation in the South was brutal and pervasive. But the underlying assumptions of white supremacy and the practices of racial segregation existed throughout the country, with perhaps equally insidious effects.

There are two types of segregation practiced against the African Americans in the North and South, namely de jure and de facto. De jure segregation involved the use of laws to enforce segregation policies, while in de facto segregation, the law was not used to enforce segregation policies but segregation still existed. In the South, de jure segregation was practiced whereby both the police and the legal system enforced segregation. The infamous Jim Crow laws ensured racial segregation in virtually all spheres of public life including education, voting, and transportation, among others. Even though such laws were absent in the North, racial discrimination was still present in almost all aspects of life including housing, employment, and education. The unending suffering sustained by the Jim Crow laws eventually led to the formation of the Civil Rights Movements to fight for equal rights and treatment for African Americans. Eventually, these laws were overturned by landmark court rulings like Brown v Board of Education, in which the Supreme Court outlawed segregation in schools.