South Mayo (UK Parliament constituency)
South Mayo was a parliamentary constituency in Ireland, which returned one Member of Parliament to the House of Commons of the Parliament of the United Kingdom from 1885 to 1922.
Prior to the 1885 general election the area was part of the two-seat Mayo constituency. From 1922 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 Connemara constituency contained in the administrative county of Mayo.
Members of Parliament
| Years | Member | Party |
| 1885–1890 | J. F. X. O'Brien | Irish Parliamentary Party |
| 1891–1895 | J. F. X. O'Brien | Anti-Parnellite |
| 1895–1900 | Michael Davitt | Anti-Parnellite |
| 1900 – January 1910 | John O'Donnell | Irish Parliamentary Party |
| January–December 1910 | John O'Donnell | All-for-Ireland League |
| 1910–1918 | John Fitzgibbon | Irish Parliamentary Party |
| 1918–1922 | William Sears | Sinn Féin |