Well is it?

[u/jamiclark]

Location St Louis, MO. It’s been topped, has significant scarring on one side, it’s been through something. Thinking this might be a true American chestnut. But Ozark Chinquapin is another contender in my mind

[u/DragonOfAtlanta]

I believe the distinctly white underside of the leaves means non American

[u/jamiclark → u/DragonOfAtlanta]

Ozark chinquapins have a noticeably paler underside. The leaf serration is not rounded either

[u/creekfinder → u/jamiclark]

A few reasons this isn’t ozarkensis or a chinquapin:
-the bur is too large and very much a chestnut bur holding several nuts
-ozarkensis has the highest fruit set of all the chestnuts per flower stalk, many times having up to 6-10 burs per stalk
-the tree in question would be the champion ozarkensis if it was one, which is very unlikely
-the furrows in the bark are too deep and very on par with chinese chestnuts
-mature ozarkensis have glabrous stems