Triangular dark shape hovering above closed ammunition plant in Southern Indiana.

My mother and I were driving back home from Clarksville, Indiana. It was dark outside and the weather was warm and clear. We were driving northeast along the road that takes you past the Jeffersonville Ammunitions Plant. We both saw it at the same time. An object in the sky with no lights. It didn't appear to be moving. The object was hovering above one of the old closed down factory sections. It wasn't really high but it wasn't what I would call low either. I would saw that it was as high as a very tall radio tower(if that makes any sense). If I had to guess how big it was, I would have to compare it to jets I have seen at airshows at that altitude. I would say about the size of a B1-B. We approached it. It was off to the east of us. It never moved from the point in that point in the sky. My mother slowed down and I stuck my head out the window for about three minutes. I never heard any noise coming from the object and there were only a couple of cars in the area but not near us. The object was dark. Not reflective that I saw. It was triangular in shape.
Date is approximate.  PD