1950–1974: The Borough of Truro, the Urban District of St Austell, the Rural District of Truro except the parish of Gwennap, and in the Rural District of St Austell the parishes of Creed, Grampound, Roche, St Dennis, St Ewe, St Goran, St Mewan, St Michael Caerhays, and St Stephen-in-Brannel.
1974–1983: The Boroughs of Truro, and St Austell with Fowey, the Rural District of Truro except the parish of Gwennap, and in the Rural District of St Austell the parishes of Creed, Grampound, Roche, St Dennis, St Ewe, St Goran, St Mewan, St Michael Caerhays, and St Stephen-in-Brannel.
1983–1997: The District of Carrick wards of Boscawen, Chacewater, Feock, Kea, Kenwyn, Moresk, Newlyn, Perranzabuloe, Probus, Roseland, St Agnes, St Clement, Tregolls, and Trehaverne, and the Borough of Restormel wards of Crinnis, Mevagissey, Poltair, Rock, St Ewe, St Mewan, St Stephen-in-Brannel, Trevarna, and Treverbyn.
The constituency has existed in a number of different forms. The constituency of Truro, up until 1885 elected two members to parliament; this was reduced to one. In 1918 the constituency was abolished but it was recreated again in 1950.
The seat became a safe Lib Dem bet thanks to the popularity and eloquence of its former MP, David Penhaligon. His death in a car crash, aged only 42, robbed the House of Commons of one of its most independent-minded and pragmatic members. His successor, Matthew Taylor, held the seat comfortably from a by-election in 1987, and remained its MP after the name change in 1997.
Another General Election was required to take place before the end of 1915. The political parties had been making preparations for an election to take place and by July 1914, the following candidates had been selected;
F. W. S. Craig, British Parliamentary Election Results 1832–1885 (2nd edition, Aldershot: Parliamentary Research Services, 1989)
Maija Jansson (ed.), Proceedings in Parliament, 1614 (House of Commons) (Philadelphia: American Philosophical Society, 1988)
Lewis Namier & John Brooke, The History of Parliament: The House of Commons 1754–1790 (London: HMSO, 1964)
J. E. Neale, The Elizabethan House of Commons (London: Jonathan Cape, 1949)
Henry Stooks Smith, The Parliaments of England from 1715 to 1847 (2nd edition, edited by FWS Craig – Chichester: Parliamentary Reference Publications, 1973)
Frederic A. Youngs jr, Guide to the Local Administrative Units of England, Vol II (London: Royal Historical Society, 1991)