This castle was strategically positioned on the old military road from Boyle to Sligo to guard the pass through the Curlew mountains, site of the celebrated 'Battle of the Curlews' of 1599 held between the forces of Red Hugh O'Donnell and the English army. It was built by Captain John St Barbe between 1590 and 1610 when he was constable of the castle, on land granted to him by James 1st adjacent to Lough Arrow. Alien control of the territory appears to have been nominal with the O'Connor's having principal strongholds at Ballinafad Castle.

The castle was built at a good vantage point from which the enemy could be observed for many miles around and it was constantly under attack from both English and Gaelic forces. It was modelled on a thirteenth century design with a circular tower at each corner, serving as good protection for the castle. On entering each tower it can be seen that the inner walls are squared.

St.Barbe died in 1628 and was succeeded by Henry Fletcher, who later had to surrender the castle to the Irish after the Insurrection of 1641. However, Cromwellian forces once again took charge in 1652 when lack of water supplies weakened the Irish resistance. Ballinafad Castle continued to be habitable long after other castles in Co.Sligo had fallen into disuse, due to its later construction and was used for the chancery inquisitions of Charles 1st for the Sligo area.
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