Diamond Hill, also called Bengooria, is an isolated mountain above Letterfrack in Connemara National Park, on the northwestern edge of the Twelve Bens. Though only 442 metres high, its separation from the range gives it a distinctive shape and sweeping views across western Connemara, including Kylemore, Ballinakill Harbour, and nearby peaks. Its Irish name, Binn Ghuaire, likely preserves the memory of Guaire Aidne mac Colmáin, a seventh-century king of Connacht, while the English name refers to glittering quartz on the mountain. Popular for its accessible scenery, it became one of Ireland’s busiest walking mountains and was reopened in 2005 after erosion led to major path and boardwalk works.