Elevation: 4,137 ft
This peak is not in the book.
Riley Butte is located in the Weiser River basin, east of Crane Creek Reservoir, in the western foothills of the West Mountains. The summit lies on public land managed by the Idaho Department of Lands, and the butte is about 1 mile north of Tennison Ridge. While not a difficult summit to surmount, it does takes some back-road driving to access.
Google Maps will get you to the Riley Butte Road on the east side of the peak. Heading south on this road will take through a cattle guard due east of the peak. Once on the south side of the cattle guard, you are on public land and you can walk up to the summit from from any place along the road. The road is passable for 2WD vehicles when dry. There are great views of the Hitt, Cuddy and West Mountains from the top.
USGS Topo: Riley Butte