Also, they had mayors and stuff, a VERY clear class division and were technically under the rule of Gondor after the Northern Kingdom fell but Gondor didn’t really have the resources or urge to do any ruling over there. Once Aragorn was in they were essentially an autonomous zone under military protection in exchange for maintaining the local roads and bridges.
I found a YouTube link in your comment. Here are links to the same video on alternative frontends that protect your privacy: