Abbeymahon Abbey is a ruined abbey situated near Timoleague, County Cork, Ireland. It was founded in 1172 by Dermot MacCormac MacCarthy, king of Desmond. The site was originally at Aghamanister and was colonized with a group of Cistercian monks from Baltinglass. Almost a century lapsed before the monks of Aghamanister decided to move to a new site; it is possible that the time had come to renew the abbey buildings and the monks took the opportunity to find a more spacious site. The monks had moved to Abbeymahon by 1278, when Diarmait MacCarthaig, son of Domnall Cairbrech, was buried in the ‘new monastery’. The new site was on the estuary of the Argideen River, just over a mile east south-east of Timoleague, on the road to Courtmacsherry. The abbots of Abbeymahon were rebuked several times in the thirteenth century for not attending the General Chapter when summoned. It is not surprising that the abbots refused to attend considering that the journey was extremely lengthy and expensive. In the taxation of 1302-1306 the income of the abbey was valued at £4, which would hardly have covered the cost of the journey. The annual income of the abbey during the 15th and 16th centuries was still a meager amount, estimated at just £18, with a potential income of £34 during peace time.