<P> Following the Civil War, poor Jews and poor Italians were the predominant demographic in Harlem . African - American residents began to arrive in large numbers in 1905 as part of the Great Migration . In the 1920s and 1930s, Central and West Harlem were the focus of the "Harlem Renaissance", an outpouring of artistic work without precedent in the American black community . However, with job losses in the time of the Great Depression and the deindustrialization of New York City after World War II, rates of crime and poverty increased significantly . Harlem's African - American population peaked in the 1950s . In the second half of the 20th century, Harlem became a major hub of African - American businesses . In 2008, the United States Census found that for the first time since the 1930s, less than half of the residents were black, comprising only 40% of the population . </P> <P> Since New York City's revival in the late 20th century, Harlem has been experiencing the effects of gentrification and new wealth . </P> <P> Harlem is located in Upper Manhattan, often referred to as Uptown by locals . It stretches from the East River in the east, to the Hudson River to the west; and between 155th Street in the north, where it meets Washington Heights, and an uneven boundary along the south that runs along either 96th Street east of Fifth Avenue or 110th Street west of Fifth Avenue . </P> <P> Central Harlem is bounded by Fifth Avenue on the east, Central Park on the south, Morningside Park, St. Nicholas Avenue and Edgecombe Avenue on the west, and the Harlem River on the north . A chain of three large linear parks--Morningside Park, St. Nicholas Park and Jackie Robinson Park--are situated on steeply rising banks and form most of the district's western boundary . On the east, Fifth Avenue and Marcus Garvey Park, also known as Mount Morris Park, separate this area from East Harlem . The bulk of the area falls under Manhattan Community Board No. 10 . In the late 2000s, South Harlem, emerged from area redevelopment, running along Frederick Douglass Boulevard from West 110th to West 138th Streets . </P>

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