I had to look it up to compare, but it is most certainly NOT hackberry. The bark is all wrong.
Morus alba, possibly. There is a mulberry of some sort on a few paces away that makes leaves that can sometimes look similar, but those are never as rough textured as these. The mulberries that are generally seen naturalized here do not resemble these at all. They have much lighter, smoother bark, and tend toward lobed leaves, especially when young.
I'll admit my tree ID skills leave much to be desired.
I did dig up a matching tree from right next to it this past spring, but barely a stump with hardly a root. The foliage didn't even fully open all season. If it survives winter we'll know much more next spring.