Many AA moved north in what became known as the Great Migration. However, in N cities they often still found discrimination and limited opportunities. AA tended to congregate in specific areas of N cities such as Harlem in NY which became overcrowded w/ attendant social problems as a result. E.g., In Harlem, AA rose from 50,000 in 1910 to 73,000 by 1920. Migrants found that educational and job opportunities were often limited. But, so many people in close proximity led to vibrant culture in the 1920s in the Harlem Renaissance.