was it the boundaries when it was New France? Illinois country was administered from New Orleans, while Indiana Country was administered from the Canadian part of NF, administered (I think) from Quebec City. South of Ohio River/East of Mississippi River wasn't really administered at all. except for the coast, it was Indian Country, claimed by France. The map above is basically France claimed New France, with Florida tacked on, and west of Mississippi given to Spain.
Alter events of New France, and Quebec may quite well extend to Ohio River, although French, and not the English so many assume.
But if you want it English, have the British be a little less pushy toward the 13 colonies after the French and Indian War. Britain had put the northwest territory into the Canadian sphere. Although it was off limits to white settlement, that could change with time. It probably gets split into a new colony, but you never know.