I don’t know if they could be considered historicals, but there are a couple of caches that I later went out of my way to research.
“I love the smell of hydraulic fluid in the Morning”, is on the site of the old Chanute Air Force Base in IL. I always enjoy midwest military history.
Another interesting one was JThorson’s now archived “The Bray Road Beast.” Some strange accounts to be found about that one also.
The one I spent the most time on was in the making of one of my own caches, “Bowen Country Club”. Lots of interesting history to be found by researching Jane Adams and Hull House.