Oak - where does it come from?

Ok, some smarty pants is going to say trees. Duh! Of course, the only reason I recognize that is it would likely be me were this be someone else's post. I digress. I just finished sanding the oak floors for the renovation. Sanding for a better part of 24 hours caused me to wonder, where does all the oak wood come from. Spruce and fir and poplar and Bamboo I get,: there are forests of them. But oak? I have no recollection of an oak forest anywhere. Is there? Maybe you can enlighten me., cause I have no clue.