The Appendix to the 34th Report of the Commissioners of Her Majesty's Woods, Forests and Land Revenues 1856, published in the House of Commons Papers Vol 37 page 145 records the purchase of parts of the Kingwilliamstown estate by James William Mackey (789 acres) and Charles Mackey (587 acres) in 1855. In the 1870s Sir James William Mackey of Dublin and Kingwilliamstown owned 1,377 acres in county Cork. He was an alderman of Dublin and had served as Lord Mayor in 1866 and 1873. He was made a knight in 1874. Sir James was the son of Stephen Mackey, a merchant of Dublin. He was born in 1816 and married Hannah Sylvia, daughter of Sylvanus Jones of Kircullen House, county Galway in 1848. Almost 600 acres, the property of Caroline Mackey, was sold in the Landed Estates Court in February 1875. The purchasers included Sir J.W. Mackey and William Blennerhassett.
National Library of Ireland:
Copy of confirmation of arms to the Rt. Hon. James William Mackey of Clonsilla House, Co. Dublin, Lord Mayor of Dublin, son of Stephen Mackey of Spring Field, Bray, Co. Dublin, Aug.20, 1866.
Genealogical Office: Ms. 109, pp. 119-20