General info, including typical sites and associations, at the link below.

You'll be hard-pressed to find them in the wilds of IN anymore.
The introduced butternut canker disease is and has decimated J.cinerea throughout its range, and current thinking is that there are no pure butternuts which are resistant. But, hybrids with the Japanese walnut, J.ailantifolia, and its bud sport, the heartnut, do exhibit varying degrees of resistance - and some 'butternut' cultivars which have been propagated for decades - some for nearly 100 years - have been determined to actually be butternutXJapanese walnut hybrids.

Here is a link that might be useful: Juglans cinerea

Around here butternuts are edge species. Fencerows, roadsides, pastures left to grow brush....but they are almost all pretty sad and sick....a species on the way out unfortunately. Can't remember the name of their downfall...Pretty sure it's a introduced enemy.

I don't think there were ever all that many here, but the few I know of are gone.

I planted some of the hybrids a couple of springs ago, and they're growing well but were only about 6-8 inches tall when I got them, and are about 3 feet now. So, it will be a while before I see nuts off of them.

Not many places where they were ever all that abundant, I don't think.
I have some pure seedlings, some hybrids, and some grafts of both pure and hybrid selections. Have never seen one 'in the wild'.
Several years back, I asked a friend, who's a consulting forester and has spent most of his life and career in this area, about butternuts, and he indicated that he'd never seen one 'in the wild', either.

Where I lived in NJ had a lot of them just in our wooded yard alone. I never would've considered getting the "Bountiful Butternut" hybrid without that part of my life. I've heard they were around here but I have never seen one in the woods.

myk1,
First 'butternut' I planted was a seedling of 'Bountiful' - no idea what the pollen parent was; came seednut came from an orchard with other butternuts/hybrids/Japanese walnuts/heartnuts. It's a nice vigorous tree with no evidence of canker disease so far, and I'm hopeful that it will produce its first crop of nuts this year.