Bonneville MountainBonneville Mountain is an mountain summit located in Wallowa County, Oregon, US.DescriptionBonneville Mountain is located eight miles south of Joseph, Oregon, in the Wallowa Mountains. It is set within the Eagle Cap Wilderness on land managed by Wallowa–Whitman National Forest. The peak is situated south of Wallowa Lake and precipitation runoff from the mountain drains west into West Fork Wallowa River and east into the East Fork. Topographic relief is significant as the summit rises over above the lake in approximately three miles.EtymologyThis landform's toponym was officially adopted in 1925 by the United States Board on Geographic Names to honor Benjamin Bonneville, an officer in the United States Army and explorer of the American West noted for his expeditions to the Oregon Country. Captain Bonneville and his party are credited with the first documented entry into the Wallowa Valley by a non-native in 1834. This mountain was originally known as Middle Mountain.ClimateBased on the Köppen climate classification, Chief Joseph Mountain is located in a subarctic climate zone characterized by long, usually very cold winters, and mild summers. Winter temperatures can drop below −10 °F with wind chill factors below −20 °F. Most precipitation in the area is caused by orographic lift. Thunderstorms are common in the summer.