It comprised the northern part of County Londonderry, defined as follows:[1] The constituency returned one Member of Parliament.
Prior to the 1885 United Kingdom general election and after the dissolution of Parliament in 1922 the area was part of the Londonderry constituency.
Sinn Féin contested the general election of 1918 on the platform that instead of taking up any seats they won in the United Kingdom Parliament, they would establish a revolutionary assembly in Dublin.
In republican theory every MP elected in Ireland was a potential Deputy to this assembly.
This area, in republican theory, was incorporated in a five-member Dáil constituency of Londonderry.