The Great Migration, sometimes known as the Great Northward Migration, was the movement of six million African-Americans out of the rural Southern United States to the urban Northeast, Midwest, and West that occurred between 1916 and 1970. In every U.S. Census prior to 1910, more than 90 per cent of the African-American population lived in the American South. In 1900, only one-fifth of African-Americans living in the South were living in urban areas. By the end of the Great Migration, over 50 per cent of the African-American population remained in the South, while a little less than 50 per cent lived in the North and West, and the African-American population had become highly urbanized. By 1960, of those African-Americans still living in the South, half now lived in urban areas, and by 1970, more than 80 per cent of African-Americans nationwide lived in cities. In 1991, Nicholas Lemann wrote that:

The Great Migration was one of the largest and most rapid mass internal movements in history—perhaps the greatest not caused by the immediate threat of execution or starvation. In sheer numbers it outranks the migration of any other ethnic group—Italians or Irish or Jews or Poles—to [the United States]. For blacks, the migration meant leaving what had always been their economic and social base in America, and finding a new one.

Some historians differentiate between a first Great Migration (1916–1940), which saw about 1.6 million people move from mostly rural areas in the south to northern industrial cities, and a Second Great Migration (1940–1970), which began after the Great Depression and brought at least 5 million people—including many townspeople with urban skills—to the north and west.

Since the Civil Rights Movement, a less rapid reverse migration has occurred. Dubbed the New Great Migration, it has seen a gradual increase of African-American movement to the South, generally to states and cities where economic opportunities are the best. The reasons include economic difficulties of cities in the Northeastern and Midwestern United States, the growth of jobs in the “New South” and its lower cost of living, family and kinship ties, and improved racial relations. As early as 1975 to 1980, several southern states were net African-American migration gainers, while in 2014, African-American millennials moved in the highest numbers to Texas, Georgia, Florida, North Carolina, and California. African-American populations have continued to drop throughout much of the Northeast, especially from the state of New York and northern New Jersey, as they rise in the South.