I don’t know this for a fact, but it is my belief that the US Bureau of the Census can give you a breakdown that you want.

Good luck with your research.

August 29, 2008, 10:05 PM EDT

According to the latest Virginia census data, the two biggest population centers for African Americans are Richmond and the Norfolk-Virginia Beach-Newport News metropolitan area. Between those two areas, Richmond is northern most, but it’s more like central Virginia.

Strictly in Northern Virginia, Alexandria city has the highest African American population (over 20% of the population/30,000 people).

sorry, I’m not usually a spell checker, but Virgina is borderline vulgar! “My cousin from the hills touched my virgina!”