The value of a given census tract (year 2000 tracts were used for basic enumeration units) corresponds with a color, ranging from the darkest blue (100% of population self-identified as “blackâ€, “negroâ€, “African-American†or whatever was the term in use for that year) to pale yellow (0% black).
A brief analysis of the maps tells us much about the historical landscape of black population change in the United States. All cities in this study followed the general trend of increasing, then decreasing concentrations of black population in the city center. One can see the percentage of blacks decrease in the peripheral areas as they simultaneously increase (and spread outwards) from the city center. This is a classic example of White Flight; white populations fleeing the dispersing black population, who began moving from the city center to inner-ring suburbs. Whites living in these suburbs then moved to outer-ring suburbs, or ex-urbs, depending on the stage.