The tallest peak in Josephine County, Ore., is Grayback Mountain at 7,050 feet.
Historians are unsure about the origin of the name, which dates from the mid-19th century. Some believe Grayback refers to the exposed granite outcroppings near the summit. Others say that Grayback was a derogatory name for Confederate soldiers during the Civil War, a term that appeared often in Jacksonville’s newspapers in the 1860s. There is some consensus that miners named the mountain after the fleas in their clothing and bedding, which they called graybacks.
O’Brien Creek flows down the east flank of Grayback Mountain as a tributary of Thompson Creek and the Applegate River. The creek was named after John O’Brien, an Irish immigrant who settled on a donation land claim near Provolt in 1852. During the summers, his cattle grazed on the green grass on Grayback Mountain. In the 1860s, he built a ditch from the creek that now bears his name, to his mining claim, just to the east on Steamboat Mountain.
A Bureau of Land Management trail constructed in 1989 by the Sierra Club and local volunteers leads to the summit of Grayback Mountain.
Sources: "Grayback Mountain Trail." U.S. Department of the Interior: Bureau of Land Management. Web. 19 Aug. 2014. http://www.blm.gov/or/resources/recreation/site_info.php?siteid=367; LaLande, Jeff. "From Abbot Butte to Zimmerman Burn: A Geographic-Names History and Gazetter of the Rogue River National Forest ." Southern Oregon Digital Archives. Rogue River-Siskiyou National Forest, Feb. 2007. Web. 19 Aug. 2014.