It's a walnut, possibly Juglans cinerea, common name Butternut, though nuts I photographed today that I thought were that species look a little different, so maybe a different species or cultivar or hybrid. I read somewhere just a few minutes ago that the Butternut leaves are fragrant, but I'm unable to find that now, didn't find that mentioned elsewhere or for other species of walnut. I didn't notice that on any walnut leaves I felt today. Maybe other people can tell from just that photo which kind of walnut it is. I'd want to see a whole leaf (with all the leaflets), and the trunk. And would want to know how many nuts are in most of the nut clusters. And even then, since they hybridize easily, I might not be able to tell what kind.
Perhaps more likely Japanese Walnut Juglans ailantifolia - closely related to Butternut and similar, but with larger leaves.