According to the Internet, post 187 is in Elmhurst Illinois. Also according to the internet, it’s in Wisconsin Dells. Thank you internet.

A TripAdvisor question from 2008:

What is the deal with the vacant area by where it says Stand Rock is on our map? There was a gate we went into to and a sign beside it. Once we got in it looked like a previously used area that has just been let go. A trailer house down at the bottom and even a recliner and junk off in the wooded area on one side. On our way out it had a "Dells Boats" sign. Evens signs saying down there "Ticketed area. purchase tickets at booth." ??

No longer nightly, it seems.