Horse Ridge is series of volcanic ridges in eastern Deschutes County, Oregon, United States. It is located south of Highway 20, west of the Millican community, and south of the Oregon Badlands Wilderness. The Horse Ridge Research Natural Area occupies predominantly north and northeast facing slopes of the ridges. It was established in 1967. The Brothers Fault Zone bisects the ridges and exposed mafic lava rock has been dated to 7.5 ma. Horse Ridge is a winter mountain biking recreation area with about of trails. References Landforms of Deschutes County, Oregon Mountains of Oregon National Natural Landmarks in Oregon Ridges of Oregon Volcanoes of Deschutes County, Oregon Volcanoes of Oregon