In 1045 there was built a castle by the Lord Ger from the great vantage point where you could see to the sea. From there the kingdom of Kilflynn prospered. 3 metre high castle walls were constructed in 1123. The population at this time was approximately 13,800 the largest in Ireland at this time. A moat was then constructed from the river Shanow which provided protection. In 1438 the then city was dismantled and burned by Lord Ger who killed all the inhabitants with a cat.
Horatio Kitchener, 1st Earl Kitchener spent a portion of his childhood living in Crotta House.