I believe you guys got it. Looks like maybe one of the Linden trees such as American Linden (aka Basswood). Thanks
Funny as the wife was talking about how they had just got back from a trip and saw a beautiful, large Basswood. The tree this leaf came off of she unfortunately used Tordon to treat some suckers at the base of it last year, so the tree is showing some herbicide damage this year. I guess time will tell if there was enough exposure to kill it. I schooled her on the use of Tordon!