While wandering my property today, I found a tree with unripe fruit (none have fallen to the ground yet, and it appears they will turn red). Most of the fruit seem larger than a golf ball. Each of them has 4-5 large white seeds on the inside, about the same size as a pumpkin seed.
I’m guessing a crabapple of some sort, but I have never seen crabapples quite so big (the ones in the picture are the smallest fruit on the tree).