The ruins of Clonderlaw Castle can be seen in the demesne of Mrs Gore in the Parish of Kilmurry Mc Mahon, Co. Clare It was once the home of the Mc Mahon chieftains who held sway over the Barony of Clonderlaw then known as the lands of Corea Baiscinn. They also had another Castle at Ballynacally the ruin of which can be seen, adjacent to the little village of that name.
Sir Teigue Mc Mahon was the last of those chiefs who ruled in Clonderlaw and local tradition has it that he ruled with a stern hand. South of Clonderlaw Bridge to the west of the road leading to Labasheeda is a rising eminence know as "Knock na Cruha" or the hanging hill. Malefactors, or those who did not obey his laws ended their lives on the gibbet erected there. One day a poor woman complained to Sir Teigue that her son was very disobedient and that he showed no sign of reforming. "All right" replied Sir Teigue "we will hang him." The old woman was in great consternation and but for Sir Teigue's right-hand-man not in the habit of revoking an order. Sir Teigue was outlawed by the British and in order to "carry on" he levied a tax on his subjects. The tax was resisted successfully by Count Cuniningham of Ayleroe and others and this hastened the downfall of the last of the Mc Mahon chieftains.
From this branch of Mc Mahon's the famous Marshal Mc Mahon of France descended