The nation’s African-American population continued its southward migration over the past decade, shifting a large part of the black middle class from northern states to faster-growing economies of the South.

Among 25 big U.S. metro areas with the largest growth in African-American population between 2000 and 2009, 16 were in the South—including Atlanta and Dallas—according to the Census Bureau’s American Community Survey. Among the big losers were cities in the North and West, including Detroit, Los Angeles and Cleveland.

The biggest gainer was Atlanta, a magnet for black professionals. Its metro area added about 500,000 African-Americans between the 2000 and 2009 period, and more than twice the next-largest numeric gainer, Dallas, according to an analysis of Census data by William H. Frey, a demographer at the Brookings Institution in Washington, D.C. Over the same period, the share of Atlanta’s 25-and-over black population that had college degrees increased to 24.6% in 2009 from 21.5% in 2000.

Other southern cities including Houston, Charlotte, N.C., and Raleigh, N.C., were also among the nation’s biggest gainers of African-Americans over the decade, each with higher-than-average growth in their black college-educated population, many of them newcomers, according to Mr. Fr

Shifts in the black population mirror larger trends. The decline of manufacturing jobs has hobbled the economies of northern states such as Michigan and Ohio, prompting residents of all races to seek better fortunes elsewhere. California also has had an exodus of residents.

Melissa Harris-Perry, 37 years old, a professor of politics and African-American studies at Princeton University, has been an observer of the shift as well as a participant. She recently moved to New Orleans from Princeton and for the time being is commuting between the cities. There were many reasons from the move, including marriage, New Jersey’s high living costs and property taxes and a desire to give her daughter the “robust black cultural experiences” that Ms. Harris-Perry says she couldn’t find in Princeton.

“We can save, we can travel, and we can get out of debt,” she says of the lower taxes and cost of living in her new state.

All this is slowly unwinding the so-called Great Migration, the 20th-century movement of blacks from the South to the growing industrial cities of the East Coast, Midwest and West. In 1960, the South had 60% of the nation’s black population. That fell to 53% by 1970. The South now has 56.8% of the nation’s non-Hispanic black population, compared with 55.1% in 2000 and 53.6% in 1990, according to Mr. Frey. Since 2000, the South has had three quarters of the nation’s Black population growth.

The movement of African-Americans has also shifted the distribution of the college-educated black population. In 2009 the metro area with the largest share of college-educated blacks was Washington D.C., just ahead of San Jose, Calif., which had the largest share in 2000.

San Jose, in the heart of California’s Silicon Valley, saw its share of African-Americans with college degrees fall as the state bled residents over the decade. Atlanta, Raleigh and Nashville, Tenn., were all among the top five cities with the largest share of 25-and-over blacks with college degrees.

Several big northern cities have fallen down on the list of cities with the highest concentration of black college graduates, though in many cases their concentration of college-educated blacks has grown as more Americans of all races have graduated from college. In 2000, for instance, the Boston metro area had the nation’s sixth-highest concentration of college-educated blacks. In 2009 the city was fifteenth among big metro areas. In Youngstown, Ohio, the metro area lost 12.3% of its black college graduates from 2000-2009, compared with a 3.2% decrease in 25-and-over blacks overall.

The movement of blacks southward, as well as the continued growth of African-Americans in suburbs, has political implications.

The growth of minority populations in general, and huge turnout among black voters in particular, were among reasons President Barack Obama, a Democrat, won in traditionally Republican states like Virginia and North Carolina in 2008.

Demographers first started noting the black southward migration in the 1970s, but the movement since has gained considerable steam. Many blacks were attracted southward for the same reasons as whites and Hispanics: The South has had fast job and population growth, attracting everyone from young people getting their first jobs to entrepreneurs looking to start businesses in a fast-growing metropolis.

Blacks in particular have sought out the South, due, in part, to fading memories of 1960s race clashes and networking opportunities in cities that already have a solid stock of African-American professionals.