1950-1983: The Urban Districts of Cookstown, Omagh, and Strabane, the Rural Districts of Castlederg, Cookstown, Magherafelt, and Strabane, and part of the Rural District of Omagh.
1983-1997: the District of Cookstown; the District of Omagh; the District of Magherafelt wards of Ballymaguigan, Draperstown, and Lecumpher; and the District of Strabane wards of Castlederg, Clare, Finn, Glenderg, Newtownstewart, Plumbridge, Sion Mills, and Victoria Bridge.