The placename itself tells the story of this ancient ford; Finnea derives from the Irish Fiodh an Átha, meaning ‘the wood of the ford’, indicating this was an important river crossing long before any castle was built here. Historical records confirm that in 1397, Roger Mortimer, Earl of March, constructed a castle at this location, taking advantage of the site’s natural defensive position and control over river traffic.

The castle’s existence is well documented in various historical sources, though no visible traces remain today. The 1657 Down Survey map of Fore Barony shows ‘Finnag Bridg’ clearly marked, whilst another Down Survey map of Foyran parish depicts a ruinous tower or castle standing in the field north of the road crossing the bridge, surrounded by a cluster of dwellings that likely represented the medieval village of Finnea. This settlement pattern, with castle, bridge and village in close proximity, was typical of Anglo-Norman strategic planning in medieval Ireland.

The site witnessed military action during the Confederate Wars, as recorded in the memoirs of James Tuchet, Earl of Castlehaven. In 1644, he described defending the stone bridge at Finnea, noting there was a castle at the southern end. Castlehaven deployed 600 foot soldiers and 100 cavalry to hold the bridge, equipped with shovels, pickaxes and plenty of ammunition, demonstrating the continued military importance of this river crossing well into the 17th century. Whilst archaeological surveys conducted in 1979 found no visible remains of the castle structure, the documentary evidence firmly establishes this as a significant medieval fortification that controlled one of Westmeath’s key river crossings for centuries.