Griffith's Valuation shows that Farrell McDonnell was in possession of a townland in the parish of Abbeyknockmoy, barony of Tiaquin, county Galway in the mid 1850s. In the 1870s Farrell McDonnell owned 149 acres in county Galway and 1,034 acres in county Roscommon. 578 acres belonging to him was vested in the Congested Districts' Board on 16 Feb 1911. By March 1916 he had received a final offer of over £18,000 from the Congested Districts' Board for his 4,500+ acres in county Galway. In March 1912 over 2,000 acres in county Roscommon belonging to him were vested in the Congested Districts' Board. He was related to Martin McDonnell as there is reference to his estate at Meelick, just south of Williamstown, [parish of Boyounagh, barony of Tiaquin] in a Dail debate. This townland belonged to Martin McDonnell at the time of Griffith's Valuation. see http://historical-debates.oireachtas.ie/D/0347/D.0347.198402150037.html Farrell McDonnell, Sweeney and Company are a firm of solicitors in Abbey Street, Roscommon. Information in the Farrell McDonnell file in Roscommon County Library records Farrell McDonnell (1845-1904) as a solicitor and the first Chairman of Roscommon County Council. He was a son of Mark McDonnell of Roscommon and Ballaghderreen and a nephew of Martin McDonnell of Roscommon and of Farrell McDonnell Senior, who had extensive business interests in Roscommon town. Possibly there were 2 Farrell McDonnells as Sister Delaney writes that Martin McDonnell of Dunmore had 2 sons James who lived at Waterslade, Tuam and Farrell, who married a daughter of Frank McDonagh of Wilmount, Portumna.
National Library of Ireland:
Estate records of Denis J. Kirwan and Sons, land agents, Tuam, mid 19th - mid 20th centuries, including account book of rents received, 1909-1921. Acc. No. 5124