Yes it was Devils Tower Wyoming. In the KOA campground that is literally just outside the entrance to Devils Tower National Monument.
And yes, in the movie, Close Encounters of the Third Kind, Richard Dreyfuss's character tried to replicate it out of mashed potatoes at the dinner table. Which is probably why they are not available at the cafe. But they do show the movie every night in the summer with the tower looming behind the screen in the distance.
Silver 2014.5 Interstate EXT