So, you guys have heard of the Great Migration, right? It's an important thing. Especially critical to keep in mind when thinking about Reconstruction. Also, slavery was banned from the Great Lakes states way back in the Articles of Confederation days. So, that's why outside of the big Industrial cities, there are still no black people in the farm country up that way.
There's also the fact that before the Civil War, quite a few of the Old Northwest states had laws that barred free blacks from settling there as well.