N 41° 40.730 W 088° 00.007
Spent the day with TeamFawlty seeking another bugger of a survey mark a few miles away, but we swung by here so I could nab this one. TF was very knowledgable about the bridge; though I've been by this bridge hundreds of times, I was able to appreciate its structure on a new level. Thanks, TF! The mark itself was iced over, but we located it at the above coords -- barely inside the "088".