An article about free person of color in Virginia that I found on the Internet (http://srnels.people.wm.edu/antrichf95/wolfson.html) indicates that there were large numbers of free Blacks in Virginia even before 1830.

Although names and races of free persons of color are found on the 1850 census roles, I find it difficult to search on Ancestry for free Black residents of Virginia in 1850. Are there any tricks to do that?

Using Heritage Quest, one can ask for a listing of all Black or mulatto persons living in a given state. Unfortunately, 1850 is not one of the years in its search database.