U.S. Census Office, Map Showing in Five Degrees of Density the Distribution of the Black Population (1874)

This choropleth map illustrates the population density of Black people in the United States "east of the 100th meridian" according to the returns of the 1870 Census. Darker shading indicates areas with higher population density. The map reveals a strong concentration of Black people in the southern states, reflecting the region’s history of slavery, which had been abolished only five years earlier at the end of the Civil War. The map also shows smaller concentrations in northern regions, including parts of New York City and lower Michigan.This visualization was included in the first Statistical Atlas of the United States (1874), a compilation of data visualizations created under the direction of Francis A. Walker to present information collected from the 1870 Census in a visual format.