This company bought the Port Royal estate of the Gildea family in the parish of Ballyovey, barony of Carra, county Mayo. In 1876 they owned 5179 acres in county Mayo. They sold 6208 acres to the Congested Districts' Board on 10 Mar 1898.
National Library of Ireland:
Westport Estate Papers, rental of the estate of the National Building and Land Investment Company, 1884-1885. MS 41,078/2