Horse Heaven Hills

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.

The region has been inhabited by Native Americans for centuries, who had settlements surrounding the Horse Heaven Hills. They used the range both as hunting grounds and as a geographic boundary between different tribes. The Lewis and Clark Expedition represents the first known Europeans to reach the area. European settlement followed, with the introduction of modern farming techniques. In recent years, wineries have become an important economic driver in the region and the Horse Heaven Hills AVA was established in 2005.

North-to-south compression of flood basalts that erupted several million years ago is responsible for the uplift that created the hills. They were further shaped by massive floods that occurred toward the end of the last ice age. The floods contained icebergs that brought glacial erratics, which stand out from the basalt that dominates the Columbia Basin.

Native grasses and shrubs dominate the range, which is mostly treeless. Flora also includes native flowers, some of which are listed as being threatened. There were at one time large numbers of big game roaming the hills, but many of them were hunted to extinction. Horses briefly roamed widely through the hills, but they were largely removed to facilitate farming. Today, wild horses are confined to near Satus Pass. There have been recent efforts to reintroduce animals that had previously been driven from the range.