Moher, Cliffs of

Spectacular sheer cliffs of dark sandstone topped by black shale in County Clare, Republic of Ireland, on the southwest edge of the Burren, overlooking the Aran Islands. Extending for 8 km/5 mi, they rise from 115 m/400 ft, at the southern extremity of Hag's Head, to a height of 200 m/700 ft. The stratified layers of shale and sandstone lie on a bed of limestone, and contain a band of unusual fossils. Breanan Mór, a 70 m/244 ft-high sea stack, stands offshore at the northern end of the cliffs. A coastal path leads along the clifftops to O'Brien's Tower, a circular folly built near the highest point by Cornelius O'Brien (1801–1857) in 1835. A visitors' centre lies 5 km/3m northwest of Liscannor.

The cliffs are named after the ancient fort of Mothar on Hag's Head, now the site of a signal tower built during the Napoleonic Wars.