Rimrock is the sheer rock wall at the upper edge of a plateau, canyon, or geological uplift. It may refer to either the rock formation or to the rock itself. Rimrock may be composed of almost any stone—basalt, gneiss, granite, sandstone, etc.—and is frequently layered. Many times it overlays a softer stone which erodes away underneath. American Indians in the West often used cavities found below rimrock to construct dwellings and granaries. Geographic placenames The geologic formation has lent its name to many places in the western United States. Communities: Rimrock, Arizona; Yavapai County, northeast of Camp Verde. Rimrock, California; San Bernardino County, east of San Bernardino. Rimrock, Montana; Yellowstone County, west of Billings. Rimrock, Washington; Yakima County, near Rimrock Lake on the Tieton River west of Yakima. Rim Rock Colony, Montana; Toole County, north of Helena. Canyons: Rim Rock Canyon, Orange County, California Rimrock Valley, Modoc County, California Rimrock Gulch, Moffat County, Colorado Rimrock Canyon, Nye County, Nevada Rim Rock Canyon, Lincoln County, New Mexico Rimrock Draw, Washakie County, Wyoming Rim Rock Draw, Johnson County, Wyoming Cliffs: Rimrocks, Yellowstone County, Montana Rimrock, El Paso County, Texas The Rimrocks, Kane County, Utah Lakes: Rimrock Lake, Modoc County, California Rimrock Lake, Carbon County, Montana Rimrock Lake, Colfax County, New Mexico Rimrock Lake, Marion County, Oregon Rimrock Lake, Yakima County, Washington Rimrock Lake, Teton County, Wyoming Rimrock Lake, British Columbia, Canada Mountains: Rimrock, Kootenai County, Idaho Rimrock Butte, Glacier County, Montana Rimrock Mountain, Hidalgo County, New Mexico Ridges: Rim Rocks, Routt County, Colorado Rim Rock, Grant County, New Mexico Rim Rock, Elko County, Nevada Rim Rock, Hood River County, Oregon High Schools: Rimrock High School in Bruneau, Idaho See also Bluff Butte Cliff Escarpment Mesa Mountains