In 1851 Martin P.Costello bought Lot 3, Cloghansmore and Knockroe, parish of Kilmainemore, barony of Kilmaine, county Mayo, from the sale of the Lewin estate in the Encumbered Estates' Court. In 1876 he owned 533 acres in county Mayo.
- Encumbered Estates' Court Rentals (O'Brien), Lewin, 8 Oct 1851, Vol 11, MRGS 39/004, (microfilm copy in NUIG); National Archives of Ireland
Contemporary printed sources
- PARLIAMENTARY PAPERS. ''Return of owners of land of one acre and upwards, in the several counties .... in Ireland''. HC 1876, LXXX: 308
- ''GRIFFITH'S VALUATION OF IRELAND'[Primary Valuation of Tenements]', 1850-1858. : Ballinrobe Union, 118
- HUSSEY DE BURGH, U. H. ''The Landowners of Ireland. An alphabetical list of the owners of estates of 500 acres or £500 valuation and upwards in Ireland''. Dublin: Hodges, Foster and Figgis, 1878. [available online at www.askaboutireland.ie] : 208