Prior to the 1885 redistribution the area was part of the Tyrone constituency.
Sinn Féin and the Independent Nationalist candidate together polled about 2,500 votes less than the Unionist received in 1918.
The constituencies in the 1918 Westminster election, including South Tyrone, also served as the constituencies of the First Dáil, established by Sinn Féin as the parliament of its self-proclaimed Irish Republic.
While in theory all Irish Westminster MPs were entitled to sit in the Dáil, in practice only Sinn Féin members attended, and South Tyrone's William Coote was listed on the roll as "as láthair" [absent].
[1] The Second Dáil used the single transferable vote constituencies of the 1921 home rule elections, in which the territory previously in South Tyrone was part of the eight-member House of Commons of Northern Ireland constituency of Fermanagh and Tyrone.