Independence Rock is located near Muddy Gap, Wyoming, on the Oregon Trail.  Pioneers used the rock as a landmark on their way across the country, with the goal to reach Independence Rock by the 4th of July in an effort to get across the mountains before snowfall.   Obviously, they didn't know Wyoming!  I have certainly seen snow in the mountains in July - and friends tell stories of snow in the foothills on the 4th.

Pioneers left their signatures on the rock and these may still be viewed today.  In fact, at one point the Mormons had people who lived at the rock during the emigration season to carve signatures in the granite.
Oh, and crazy people climb the rock.  If you squint carefully, you might be able to see some tiny rock climbing crazy people in this picture.