South Mayo was a parliamentary constituency in Ireland, which returned one Member of Parliament (MP) to the House of Commons of the Parliament of the United Kingdom, elected on a system of first-past-the-post, from 1885 to 1922.

Prior to the 1885 general election the area was part of the two-seat Mayo constituency. From 1922, on the establishment of the Irish Free State, it was not represented in the UK Parliament.

Boundaries This constituency comprised the southern part of County Mayo. In 1918, the constituency expanded to take in the district electoral divisions of Ballinchalla and Owenbrin from County Galway which had been transferred into County Mayo under the 1898 Local Government Act.

1885–1918: The baronies of Clanmorris and Kilmaine, that part of the barony of Costello contained within the parishes of Aghamore, Annagh, Bekan and Knock, and that part of the barony of Carra contained within the parish of Ballyovey.

1918–1922: The existing South Mayo constituency together with that part of the Galway Connemara constituency contained in the administrative county of Mayo.

Members of Parliament YearsMemberParty 1885–1890 J. F. X. O'Brien Irish Parliamentary Party 1891–1895 Irish National Federation 1895–1900 Michael Davitt Irish National Federation 1900 – January 1910 John O'Donnell Irish Parliamentary Party January–December 1910 All-for-Ireland League 1910–1918 John Fitzgibbon Irish Parliamentary Party 1918–1922 William Sears Sinn Féin

Elections

Elections in the 1880s

Elections in the 1890s

Elections in the 1900s

Elections in the 1910s

References