The  O' Connor family ruled the area around Croghan from the 13th century to the 16th century. In 1385 Murrough O' Connor defeated the English of Meath in a battle fought at Togher in Croghan.
O' Connor Faly was known in the 1500's as the greatest danger to the Pale. The pale was the part of Ireland ruled by the English at this time. The English Viceroy Anthony St. Leger attacked O' Connor's castle at Croghan in 1546. After the Plantation of Offaly in 1556 O' Connor and his family fled to Connacht. The plantation of Offaly began as early as 1536 because O' Connor's lands were constantly under attack. Brian O' Connor was often in trouble with the English and sentenced to death and pardoned many times.
 The reign of O' Connor Faly ended in 1546 when the castle at Croghan was destroyed by Brabazon and Allen. They used the stones to build a new castle at Daingean. In 1548 the O' Connors made their last stand. They were defeated and Brian was sent to London while his cousin Cahir O' Connor was hanged.
In 1597 the leader of the O' Connors returned to fight with Tyrrell at the Battle of Tyrrellspass. He fought well as the poem said ;

And still 'tis told in stories old
How from his swollen hand,
When ceased the fight the blacksmith filed
O'Connors trusty brand.

The remains of the castle are still to be seen at a height of 10 metres.These are now parts of Matt Moores farm building.

 
  By Cathal Galvin