The Copperwall Mountains, often simply called the Copperwalls, were a mountain range on the planet Sphinx. (HH3) It was very near the Harrington Homestead and was home to several treecat clans, including Bright Water, High Crag, Black Rock and at one time the Sun Shadow Clan. (HH7, HHA1.1: ABF) In 1904 PD, Honor Harrington flew in a hang glider over them near the Tannerman Ocean. (HH3) In 1922 PD, the Black Rock Clan was almost completely wiped out in the aftermath of Operation Oyster Bay. (HH12, HH13)