[DoodleDawg]

Even after that, blacks still faced discrimination in the Indian territories, with many tribes passing laws similar to the infamous “Black Codes” in the South.

Lot of that going around post war, and for many years afterwards in all parts of the country.

[DrewsMum]

Yep... the Black Codes weren’t exclusive to the South.
But somehow when it’s mentioned, it’s always followed by “in the South”.