Bread Loaf Rock was and is on the hillside between Horseshoe Bend and Boise in Boise County. You could look down from the roadway and see it, if you didn’t look too long and drive off one of the switchbacks. It looks like a bread loaf with the end slice cut off and ready to serve in front of it. In case you couldn’t see that for yourself, people used to paint the end of it white so it stood out. It’s still there, but that winding, sawdust-filled (really) road that kept slipping off the mountain is no longer the main route. The road is much improved, but the bread loaf is mostly hiding. You can still see it from a pullout, but the angle isn’t as good as it once was.
It’s not the most spectacular rock formation one could see, but countless kids enjoyed pointing it on road trips.
By the way, in looking for images of this I discovered that there are a few other rocks with that name around the country, including one at the City of Rocks National Reserve.