Site of Castle, Knockalegan, Co. Mayo
In the countryside of County Mayo, the remains of Knockalegan Castle sit on average pasture at the eastern edge of a broad expanse of flat, damp ground.
Site of Castle, Knockalegan, Co. Mayo
What survives today is a low, grass-covered rectangular mound measuring roughly 18 metres east to west and 12 metres north to south, with a well-defined scarp on its southern and western sides. The location offers excellent views to the southwest, west and northwest, whilst a north-south ridge rises gradually about 40 metres to the east, limiting visibility in that direction. A small hillock approximately 60 metres southeast of the castle site forms a spur of this ridge.
The castle’s history can be traced through old Ordnance Survey maps; the 1838 edition shows it as a rectangular building marked ‘Castle (ruin)’ with what appears to be a rectangular walled enclosure, possibly a bawn, immediately to the north. By 1930, the map depicts only an oblong hachured feature labelled ‘Castle (Site of)’, with the northern enclosure no longer shown. Today, the mound’s northern and eastern edges are poorly defined and partially obscured by scattered heaps of large boulders, with an irregular cairn of loose stones at the eastern end. Whilst some of this stone scatter may be displaced rubble from the original castle, much appears to be the result of agricultural field clearance over the years.
The eastern edge of the mound appears truncated and irregular, suggesting it may have originally extended 10 to 13 metres further east than its current dimensions. Dense nettles grow across the top of the mound, with a broad band of nettles running east to west along the northern base, possibly marking the line of a long-demolished wall. No obvious pieces of masonry, cut stone or in situ walling remain visible in the mound itself, though faint traces of the rectangular enclosure shown on the 1838 map can still be detected to the north of the site.





