- Caernarfon 1983-
- Caernarvon 1950-1983
- Caernarvon District of Boroughs 1660-1950
- Caernarvonshire 1918-1950
- Caernarvonshire 1660-1885
- Caerphilly 1918-
- Caithness 1832-1918
- Caithness and Sutherland 1918-1997
- Caithness, Sutherland and Easter Ross 1997-
- Calder Valley 1983-
- Callington 1660-1832
- Calne 1660-1885
- Camberwell Dulwich 1885-1974
- Camberwell North 1885-1950
- Camberwell North West 1918-1950
- Camberwell Peckham 1885-1974
- Camberwell and Peckham 1997-
- Camborne 1885-1950
- Cambridge 1660-
- Cambridge South West 1983-1997
- Cambridge University 1660-1950
- Cambridgeshire 1660-1983
- Cambridgeshire North East 1983-
- Cambridgeshire North West 1997-
- Cambridgeshire South 1997-
- Cambridgeshire South East 1983-
- Camden Hampstead 1974-1983
- Camden Holborn and St Pancras South 1974-1983
- Camden St Pancras North 1974-1983
- Camelford 1660-1832
- Cannock 1918-1983
- Cannock Chase 1997-
- Cannock and Burntwood 1983-1997
- Canterbury 1660-
- Cardiff Central 1983-
- Cardiff Central 1918-1950
- Cardiff District of Boroughs 1660-1918
- Cardiff East 1918-1950
- Cardiff North 1950-
- Cardiff North West 1974-1983
- Cardiff South 1918-1950
- Cardiff South East 1950-1983
- Cardiff South and Penarth 1983-
- Cardiff West 1950-
- Cardigan 1974-1983
- Cardigan District of Boroughs 1660-1885
- Cardiganshire 1660-1974
- Carlisle 1660-
- Carlow 1802-1922
- Carlow 1801-1885
- Carlton 1950-1983
- Carmarthen 1918-1997
- Carmarthen District of Boroughs 1660-1918
- Carmarthen East and Dinefwr 1997-
- Carmarthen West and Pembrokeshire South 1997-
- Carmarthenshire 1660-1885
- Carmarthenshire Eastern 1885-1918
- Carmarthenshire Western 1885-1918
- Carrick, Cumnock and Doon Valley 1983-2005
- Carrickfergus 1802-1885
- Carshalton 1918-1974
- Carshalton and Wallington 1983-
- Cashel 1801-1870
- Castle Point 1983-
- Castle Rising 1660-1832
- Cavan 1832-1885
- Cavan East 1885-1922
- Cavan West 1885-1922
- Central Ayrshire 1950-1974
- Ceredigion 1997-
- Ceredigion and Pembroke North 1983-1997
- Charnwood 1997-
- Chatham 1832-1918
- Chatham and Aylesford 1997-
- Cheadle 1950-
- Chelmsford 1885-1997
- Chelmsford West 1997-
- Chelsea 1832-1974
- Chelsea 1983-1997
- Cheltenham 1832-
- Chertsey 1885-1974
- Chertsey and Walton 1974-1997
- Chesham and Amersham 1974-
- Cheshire 1660-1832
- Cheshire Eastern 1868-1885
- Cheshire Mid 1868-1885
- Cheshire Northern 1832-1868
- Cheshire Southern 1832-1868
- Cheshire Western 1868-1885
- Chester 1660-
- Chester-le-Street 1885-1983
- Chesterfield 1885-
- Chesterton 1885-1918
- Chichester 1660-
- Chigwell 1950-1974
- Chingford 1983-1997
- Chingford and Woodford Green 1997-
- Chippenham 1660-1983
- Chipping Barnet 1983-
- Chislehurst 1918-1997
- Chorley 1885-
- Christchurch 1983-
- Christchurch 1660-1918
- Christchurch and Lymington 1974-1983
- Cirencester 1660-1918
- Cirencester and Tewkesbury 1918-1997
- Cities of London and Westminster 1997-
- Cities of London and Westminster 1950-1974
- Cities of London and Westminster Paddington 1974-1983
- City of London 1660-1950
- City of London and Westminster South 1974-1997
- Clackmannan 1983-1997
- Clackmannan and East Stirlingshire 1950-1974
- Clackmannan and Eastern 1918-1950
- Clackmannanshire and Kinross-shire 1708-1918
- Clare 1802-1885
- Clare East 1885-1922
- Clare West 1885-1922
- Clay Cross 1918-1950
- Cleethorpes 1997-
- Cleveland 1885-1974
- Cleveland and Whitby 1974-1983
- Clitheroe 1660-1983
- Clonmel 1801-1885
- Clwyd North West 1983-1997
- Clwyd South 1997-
- Clwyd South West 1983-1997
- Clwyd West 1997-
- Clydebank and Milngavie 1983-2005
- Clydesdale 1983-2005
- Coatbridge 1918-1950
- Coatbridge and Airdrie 1950-1983
- Coatbridge and Chryston 1997-2005
- Coatbridge, Chryston and Bellshill 2005-
- Cockermouth 1660-1918
- Colchester 1997-
- Colchester 1659-1983
- Colchester North 1983-1997
- Colchester South and Maldon 1983-1997
- Coleraine 1832-1885
- Colne Valley 1885-
- Combined English Universities 1918-1950
- Combined Scottish Universities 1918-1950
- Congleton 1983-
- Consett 1918-1983
- Conway 1950-1983
- Conwy 1983-
- Copeland 1983-
- Corby 1983-
- Corfe Castle 1677-1832
- Cork 1832-1885
- Cork 1802-1922
- Cork East 1885-1922
- Cork Mid 1885-1922
- Cork North 1885-1922
- Cork North East 1885-1922
- Cork South 1885-1922
- Cork South East 1885-1922
- Cork West 1885-1922
- Cornwall 1660-1832
- Cornwall Eastern 1832-1885
- Cornwall North 1950-
- Cornwall Northern 1918-1950
- Cornwall South East 1983-
- Cornwall Western 1832-1885
- Cotswold 1997-
- Coventry 1660-1945
- Coventry East 1945-1974
- Coventry North 1950-1974
- Coventry North East 1974-
- Coventry North West 1974-
- Coventry South 1950-1974
- Coventry South 1997-
- Coventry South East 1974-1997
- Coventry South West 1974-1997
- Coventry West 1945-1950
- Crawley 1983-
- Crewe 1885-1983
- Crewe and Nantwich 1983-
- Cricklade 1660-1918
- Cromartyshire & Nairnshire 1708-1832
- Crosby 1950-
- Croydon 1885-1918
- Croydon Central 1974-
- Croydon East 1950-1955
- Croydon North 1997-
- Croydon North 1918-1955
- Croydon North East 1955-1997
- Croydon North West 1955-1997
- Croydon South 1918-1950
- Croydon South 1955-
- Croydon West 1950-1955
- Cumberland 1660-1832
- Cumberland Eastern 1832-1885
- Cumberland Northern 1918-1950
- Cumberland Western 1832-1885
- Cumbernauld and Kilsyth 1983-2005
- Cumbernauld, Kilsyth and Kirkintilloch East 2005-
- Cunninghame North 1983-2005
- Cunninghame South 1983-2005
- Cynon Valley 1983-
2,145 constituencies in total