Historical records mention this castle between 1336 and 1595, though it may have an even older history; some scholars suggest it could be the castle of Lugha that was destroyed by O’Conor in 1270. The location is strategic, with the western stream joining another waterway about 100 metres to the south, providing natural defences and water access that would have been crucial for any medieval fortress.

The castle ruins sit within the northwest corner of a rectangular enclosure that measures approximately 45 metres east to west and 30 metres north to south. The northern wall of this enclosure still stands at about 1.4 metres high with a thickness of 0.9 metres, giving visitors a sense of the original defensive perimeter. Unfortunately, quarrying activities have damaged the southern portion of the site over the years, and you can spot at least one hut site within the enclosure, marked by a grass-covered spread of stones ranging from 1.7 to 2.8 metres wide and up to 0.9 metres in height.

Archaeological interest in the site has been ongoing, with test excavations carried out in 1997, 1998, and 2006 attempting to uncover more about its past. Whilst these investigations haven’t yielded significant archaeological finds, the site remains protected under a preservation order from 1979, recognising its importance to Irish heritage. The absence of material culture from the excavations adds an intriguing element of mystery to Castlemore; what remains visible above ground may only hint at the full story of this Costello stronghold and its role in the turbulent medieval politics of Connacht.