jkr doesnt understand anything about america if she thinks the northern and southern states will share the same wizarding school lollll. like the south would have formed its own school anyways after, if not before or during the civil war?
hell east coast and west coast magic has got to be different (european settlers on the east, mexican/hispanic in the whole new mexico, arizona, cali area).
not to mention historically black wizarding schools would have absolutely been a thing bc african magic survived thru slavery hello??? not to mention under slavery and jim crow laws i highly doubt black children would have been allowed to study with white students. you could even make the assumption that white slavers forbade them for using their magic at all (african magic = dark magic and all that Fun Racism)
underdeveloped and struggling to thrive native american reservation schools of magic in the dakotas?
texas has to have its own school on its own school. like its just a given fact. TEXAS WIZARDING SCHOOL QUDDITCH (like texas high school football #texasforever)
and obviously you have the elitist new england schools which everyone assumes is the pinnacle of american magic education lol