This cache is part of a 1:133,700,000 scale model of the solar system. The dome on the Monroe County Courthouse in downtown Bloomington, Indiana serves as the model of the Sun.
I know I said I was done hiding asteroids because the only ones left were so ridiculously small, but I decided to hide a few ridiculously small asteroids just for the hell of it. How small? Well the dimensions of Hygiea are about 515×396×360 km, give or take 10-20 km, making it the fourth largest asteroid in the asteroid belt. If you could place it on the surface of the Earth, it would be just big enough to cover Georgia (either the state or the country; they're about the same size). The model's dimensions are roughly 4x3x2 mm. I learned my lesson from the other asteroids falling off, so this time, the model is tied to the cache.
Even if you've heard of a few asteroids, you probably haven't heard of this one, despite it being so large. The reason is that Hygiea is quite dark in color, making it much harder to see than some of its smaller, brighter neighbors. Hygiea has a pretty eccentric orbit, so it can get pretty far from the sun (and the Earth), making it even harder to see. It ranges from about 414 to 525 million kilometers from the sun, so I placed its model about 3.20 miles from the courthouse.
Hygiea was discovered in 1849 in Naples and there was some nonsense about naming it after a ruling family, but eventually astronomers settled on naming it after the Greek goddess of health Hygieia. For years, nobody could agree on how to spell it, but eventually the second "i" was dropped and we ended up with the spelling we have today.