It not only went on in the north.
The mill villages in Alabama lasted until at least the 1960's. The town of Siluria AL. was completed owned by the one family who owned the cotton mill there. They paid for work in the factory with script that could only be used in the company store, with the company doctor and denist. The size and location of your house was determined by the importance of your job at the mill. The foremans got the house on the corner. If you had sons that were star athletics on the high school football team, you got a better job at the mill and a better house.
The same thing was happening in the Lincoln Mill Village in Huntsville at that time.

Was this a form of slavery in the 1960's in Alabama?
You could quit your job and move out of the company house anytime you wanted to. The trouble was the whole family worked in the mill, father, mother and children. When you moved you had no furniture to take with you. Most important you had no job skills but as a mill worker. The only option you had was to find another mill and start over, most likely bringing home less script.