Many celebrate 1789 as the ending of slavery in the United States of America, though in actuality the ban of slavery in the Northwest Territory and later the Bill of Rights were only written into the legislation that year, but it wasn't until the early 1790s that the abolition of slavery really began to take effect. While many states of the union allowed slaves at the time, it was felt to be a dying institution, and counter to the spirit of freedom that the new nation wished to foster. While there was some federal funds voted for recompense for freed slaves, many slave owners chose instead to sell their slaves south to the British colonies there, getting a better price than that offered by Congress, even with the downturn in price by the flooding of the slave market.
While some slave owners migrated to the Southern Colonies with the passage of abolition, the majority preferred the loss of their slaves to living once more under the rule of the Crown. Even though many slaves were sold from Maryland and Virginia, a sizable number remained with their previous owners and continued to work the land, typically in return for some share of the crop. Some likened the relation to manorialism, with the plantation owners acting as feudal lords and freed slaves as serfs.
Obviously, the Southern Colonies saw a significant increase in their slave population, just in time for the onset of a massive growth in cotton cultivation with the invention of the Cotton Engine.