The Cliffs of Moher are sea cliffs located at the southwestern edge of the Burren region in County Clare, Ireland. They run for about 14 kilometres. At their southern end, they rise 120 metres above the Atlantic Ocean at Hag's Head, and, 8 kilometres to the north, they reach their maximum height of 214 metres just north of O'Brien's Tower, a round stone tower near the midpoint of the cliffs, built in 1835 by Sir Cornelius O'Brien, then continue at lower heights.