The Great Migration generally refers to the massive internal migration of Blacks from the South to urban centers in other parts of the country. Between 1910 and 1970, an estimated 6 million Blacks left the South. This graphic compares the early migration (1910-1940), sometimes referred to as the First Great Migration, and the later (1940-1970) also known as the Second Great Migration.

In the early 20th century, strict legislation limited immigration into the U.S. and brought about a shortage of labor in many industrial and manufacturing centers in the Northeast and Midwest. These cities became common destinations for Black migrants from the South. Cities that experienced substantial changes in racial composition between 1910 and 1940 include Chicago, Detroit, New York City, and Philadelphia. During and after WWII, Black migrants flooded into many of the cities that were destinations before the war, following friends and relatives that had made the journey earlier. Poor economic conditions in the Jim Crow South spurred a larger migration flow than was the case in the 1910-to-1940 period and resulted in the creation of large Black population centers in many cities across the Northeast, Midwest, and West.

NOTE: Data are from decennial censuses, 1910 through 1970. Population counts are based on unrevised numbers. Data for the Black population for cities in Alaska and Hawaii were not available in 1940 or earlier decades. Cities shown are those that were either in the top 100 cities in the country or top 3 of a state and had a Black population of at least 100 people. These criteria were placed on 1940 data for the First Great Migration and 1970 data for the Second Great Migration.