So what do the actual numbers of black slave owners and their slaves tell us? In 1830, the year most carefully studied by Carter G. Woodson, about 13.7 percent (319,599) of the black population was free. Of these, 3,776 free Negroes owned 12,907 slaves, out of a total of 2,009,043 slaves owned in the entire United States, so the numbers of slaves owned by black people over all was quite small by comparison with the number owned by white people. In his essay, ” ‘The Known World’ of Free Black Slaveholders,” Thomas J. Pressly, using Woodson’s statistics, calculated that 54 (or about 1 percent) of these black slave owners in 1830 owned between 20 and 84 slaves; 172 (about 4 percent) owned between 10 to 19 slaves; and 3,550 (about 94 percent) each owned between 1 and 9 slaves. Crucially, 42 percent owned just one slave.
Pressly also shows that the percentage of free black slave owners as the total number of free black heads of families was quite high in several states, namely 43 percent in South Carolina, 40 percent in Louisiana, 26 percent in Mississippi, 25 percent in Alabama and 20 percent in Georgia. So why did these free black people own these slaves?”
Source: Did Black People Own Slaves?