Thomas Blennerhassett was leasing this property to Robert Conway Hurley at the time of Griffith's Valuation, when it was valued at £20. n the 1830s the Ordnance Survey Name Books describe it as the seat of Thomas Blennerhassett, who had built it in 1835. In 1786 Wilson had noted a seat of the Blennerhasset family close to the Rowan house, Ratanny. Bary states that Shanvally was built by the Blennerhassetts as a hunting lodge, possibly in the late eighteenth or early nineteenth century. It is still extant and occupied.