The stronghold belonged to the McGeoghegans, who held power as chiefs of Moycashel throughout the medieval period. Historical records paint a picture of its former glory; the 1655 Down Survey map depicts it as a tower house with a flag pole rising from its battlements, marking it as a seat of local authority. At that time, the castle stood on lands belonging to Ross Geoghegan, recorded rather pointedly as an ‘Irish Papist’ in the colonial documentation of the era.

By the early 19th century, the castle had already fallen into ruin. Larkin’s 1808 map of County Westmeath shows the site marked as castle ruins, whilst a contemporary account from 1806 refers simply to ‘Moycashel castle ruins’. Samuel Lewis, writing in 1837, noted that some remains of the ancient McGeoghegan castle were still visible, though time had clearly taken its toll on the once formidable structure.

Today, no surface traces of Moycashel Castle remain visible to visitors walking the site. Archaeological surveys conducted in 1983 confirmed that the castle had been completely levelled, though aerial photography has revealed an intriguing oval cropmark that may indicate where the tower house once stood. These ghostly outlines in the grass serve as the only physical reminder of a fortress that once symbolised the power and authority of one of Westmeath’s most prominent Gaelic families.