The Horse Heaven Hills are a long range of high, rolling hills in Klickitat, Yakima, and Benton counties in Washington. The hills are an anticline ridge in the Yakima Fold Belt formed by north–south compression of lava flows in the Columbia River Basalt Group. The highest point is Bickleton Ridge in the west end of the hills. They lie within the rain shadow to the east of the Cascade Range, making them significantly drier and hotter than regions west of the Cascades.